1
PART 1
2

Distinguish between the role of airports in the
national economy and local, regional and state
airport economic impact reports.
 Estimate the national economic contribution of the U.S.
airport system to the national economy
 Estimate how changes in airport services (nonstop flights,
air cargo transported and cost of air travel) affect the
national economy
3
Four questions were investigated to trace the impacts
of U.S. airports on the national economy:
What are the national economic impacts of U.S. airports?
To what extent do improvements in national and
international connectivity add to the national productivity
of U.S. industries?
What is the inter-relationship between air cargo and the
U.S. industrial base?
How do changes in domestic and international airfare
effect the national economy?
4

The static analysis of the national economic impacts of airports reports the
economic footprint of airports within the national economy. This is similar to
traditional methods of accounting for economic impacts of airports or airport
systems, except it does not include redistribution of economic effects within the
United States.

The dynamic analysis of connectivity estimates the growth in GDP resulting from
a change in nonstop service among airports. Connectivity refers to the total
resource costs in time and out-of-pocket expenditure to move between two
places. The connectivity analysis estimates the economic impacts of cost
changes due to changes in connectivity.

The dynamic analysis of air cargo estimates the interrelationship between air
cargo and industry productivity as measured by changes in GDP.

The dynamic analysis of airfare traces the difference between what consumers
are willing to pay for a good or service and what they actually pay. In the context
of air service, the difference between willingness to pay for air service and what
is actually spent leaves money in households’ “wallets,” and is available to be
spent in the general economy on non-aviation goods and services.
5
1
Determine How Changes in
Airports/Aviation Affect U.S.
Economy
DYNAMIC
STATIC
Assess Contribution of Airports to
National Economy
On- Airport Aviation Related
Activity
2
•Improved Connectivity by Nonstop
Flights
•Relationship of Air Cargo and
Industry Productivity
Inflow of Income to the U.S.
Due to Airports
•Sale of Exports to International
Markets
•Spending by International Visitors in
U.S. Economy
Connectivity
3
Airfares
•Lower Costs of Air Transportation as
a Consumer Benefit
6
Dollar Measurement
Definition
Labor Income
Compensation for work, including gross wages, salaries,
proprietor income, employer provided benefits and taxes paid
to governments on behalf of employees.
Value Added/GDP
The value added of a company or an industry consist of
compensation of employees, taxes paid on production and
imports, and gross operating surplus. Value added equals the
difference between an industry’s gross output and the cost of
its intermediate inputs. Value added for companies across
industries and across the U.S. is “gross domestic product.”
Output
Value added plus the cost of its intermediate inputs (including
energy, raw materials, semi-finished goods, and services that
are purchased from all sources). This is largely the value of
sales or receipts and other operating income along with any
inventory change.
7
PART 2
8
Analysis
Direct Contribution
Total Contribution
(Including Direct, Indirect & Induced
Multiplier Effects)
Static Analysis
U.S. Airports
$247 Billion
$768 Billion
$1.5 Billion
$4 Billion
1% Increase in Air Cargo
Transported (Weight)
$742 Million
$2.5 Billion
1% Reduction of Airfare for
Personal Travelers
$249 Million
$700 Million
Dynamic Analyses
1% Increase in Nonstop
Connectivity Among Airports
The national contributions of 1% changes in connectivity and air cargo are estimates based on a sample
of metropolitan regions 20 regions and should be considered illustrative. Values are in 2010 dollars.
9
1
Static contribution of U.S. Airports in the national
economy
 Similar to airport, regional, and state economic impact
studies
 Generally measures jobs, labor income, value added, and
business sales (total output) generated by: airport
administration, businesses and government agencies located
on-airport, on-airport construction spending, off-airport
spending by visiting passengers, the contribution to industry
of providing air cargo services, and, at times, the impact of
off-airport aeronautical industries.
10
International Air
Cargo
Off-Airport Spending
of International Air
Arrivals Net of
Spending by U.S.
Residents on
International Travel
On-Airport
Transactions
NOT COUNTED:
 Civil Aviation – Aircraft
Manufacturing & Parts
National
Economic
Impact of
U.S. Airports
 Domestic Air Cargo
 Off-Airport Spending of
Domestic Air Visitors
11
Measures what airports add to the national economy:
1.
On-airport commerce
2.
International cargo (brings income to the U.S. from other countries)
3.
Spending of international visitors who arrive by air
Does not include flows between domestic (U.S.) airports, which
redistributes impacts within the U.S.:
1.
Domestic air cargo are purchases and sales within the U.S.
2.
Spending of domestic air visitors represent shifting of spending from one
U.S. region to another
Also, does not include impacts of related off-airport aeronautics
industries.
12
Misc Categories & Other
10%
General managers
1%
Statistical employees
2%
General aircraft traffic
handling employees
5%
Airport operation workers
15%
Cargo handling employees
6%
Passenger/general services &
administration
14%
Maintenance employees
8%
Transport related employees
14%
Pilots & copilots
11%
Passenger handling
employees
14%
13
Visitor spending represents the net difference of spending by international travelers to the U.S.
minus spending by U.S. residents traveling internationally
Jobs
Spending
Retail,
$6.8, 23%
Amusement/
entertainment,
$3.3, 11%
2,731
TRAVEL ARRANGEMENT
Lodging,
$8.4, 29%
18,732
TRANSPORTATION
RETAIL
Food services
and drinking
places,
$6.5, 22%
30,257
ENTERTAINMENT
50,562
HOTEL
Travel agents,
$0.4, 2%
72,482
RESTAURANT
Local Surface
Domestic Air Transportation,
$1.6, 5%
Transportation,
$2.3, 8%
109,116
0
14
50,000
100,000
Jobs
150,000
Air Transportation,
458,000, 21%
International Air
Cargo, 918,900, 42%
State, Local and
Federal Employment
including TSA,
150,700, 7%
International Visitor
Spending, 314,100, 15%
On Airport
Construction,
84,200, 4%
Total Direct Employment on National Economy = 2,172,200
15
Support Activities
for Air
Transportation,
159,000, 7%
Non-Aeronautical
Revenues, 87,300,
4%
Output
Value Added
(GDP)
Labor
Income/Profits
16
Economic Impact
Source
On-Airport
Activities
International
Visitor Spending
International Air
Cargo
Total
Jobs
Labor Income Value Added
2,502,600 $144.9 Billion $242.0 Billion
518,400
$19.2 Billion
Output
$448.9 Billion
$31.6 Billion
$52.6 Billion
4,607,800 $288.4 Billion $494.8 Billion
$1.096 Trillion
7,628,800 $452.5 Billion $768.4 Billion
$1.597 Trillion
Total impacts include direct, and indirect and induced multiplier effects. Employment is rounded to the nearest 100, and dollars
are in 2010 value
Sources: BEA, Office of Travel and Tourism Industries of the U.S. Department of Commerce, BLS-CES, U.S. Census Bureau, U.S.
Budget, FAA Form 127 & National Plan of Integrated Airport Systems (NPIAS) Report, ACI-NA, U.S. Department of Commerce
data and other federal data assembled by IMPLAN. LLC. Calculations by EDR Group using 2012 National IMPLAN model.
17
5.8%
6.0%
Percent of U.S. Economy
5.0%
4.8%
4.9%
Labor Income
GDP
4.3%
4.0%
3.0%
2.0%
1.0%
0.0%
Employment
Total Output
Includes direct impacts & indirect and induced multiplier effects. Calculations based on national data sets and
U.S. Bureau of Economic Analysis, using IMPLAN, LLC.
18

Assembled 1,000+ airport economic impact
studies

Studies varied by time, location, classification of
airports & methodologies

Objective was to compare this approach to the
assembly of the preceding national databases
for the 3,330 NPIAS airports

Objective to estimate economic output
generated “on-airport”
19
Independent Variables Considered
NPIAS* Database
(3,330 airports)
•Airport Facility Descriptions
•Classification
•Runway length(s)
•Location
•Tower, etc.
• Aviation Activities
•Operations
•Enplanements
Additional Data
• Socio-economic data per county/MSA**
• Income
• Poverty
• Population
• Per capita personal income
• Distress composite index (based on
ARC)
• Employment/industry
*National Plan of Integrated Airport Systems Report, Federal Aviation Administration
**The United States Office of Management and Budget designates metropolitan statistical areas (MSA) . Each
MSA must have at least one urbanized area of 50,000 or more inhabitants.
20
Excludes off-airport visitor spending and cargo impacts
Basis of Analysis
Jobs
Labor Value
Output
Income Added
Method 1
Aggregated 2.5
$145
Databases million billion
$242
billion
$449
billion
Method 2
Regression
2.9
$164
Analyses million billion
$261
billion
$471
billion
On-airport impacts are validated by the regression analysis
21
Dynamic: if changes at airports occur, the consequence will be
increases in national productivity across U.S. industry sectors.
The Effects of Three Potential Changes Are Explored:
1.
Strengthening connections among U.S. airports and between
U.S. and international airports
2.
Increasing air cargo transported through U.S. airports
3.
Decreasing airfares for personal travelers
22
1. Connectivity of Airports
2. Inter-relationship of air cargo and industry productivity
3. Impacts of changes in air travel costs
ELEMENT
EFFECT
ECONOMIC IMPACTS
Initial from Analysis Subsequent Modeling
23
2

Connectivity
 Improved connectivity has direct effects
(costs and time) and can have indirect effects,
for example, by increasing accessible market
size and reducing costs in the supply chain.
24
Two or More Daily Nonstop Domestic Flights
International Nonstop Destinations
Domestic Nonstop Destinations
Percent of the World GDP Served Daily
Five or More Daily Nonstop Domestic Flights
Airline Hubs Served-Domestic
International Nonstop Departures
Percent of the World GDP Served Nonstop
Domestic Nonstop Departures
Percent of the World GDP Served Twice or More Daily
Number of Airlines
Note: 18 connectivity variables were analyzed. The table above shows the
variables that proved significant for one or more industries.
25
Code/ MultiAirport Region
SF Bay
Chicago
ATL
CVG
STL
PIT
RDU
DEN
Phoenix
SLC
Boston
PHL
DTW
SAN
PDX
TPA
MCI
TUL
SAT
BNA
Airport/Region
San Francisco Bay Area
Chicago metropolitan region
Hartsfield-Jackson Atlanta International Airport
Cincinnati/Northern Kentucky International Airport
Lambert-St. Louis International Airport
Pittsburgh International Airport
Raleigh-Durham International Airport
Denver International Airport
Phoenix metropolitan region
Salt Lake City International Airport
Boston metropolitan region
Philadelphia International Airport
Detroit Metropolitan Wayne County Airport
San Diego International Airport
Portland International Airport
Tampa International Airport
Kansas City International Airport
Tulsa International Airport
San Antonio International Airport
Nashville International Airport
26
Airports in Multi-Airport
Regions
SFO, OAK, SJC
ORD, MDW
PHX, AZA
BOS, MHT, PVD
NAICS Code
31-33
42
51
52
53
54
55
56
71
72
11, 21, 22,
44-45, 4849, 61, 62, 81
and 92
Sector
Manufacturing
Wholesale Trade
Information
Finance and Insurance
Real Estate and Renting and Leasing
Professional, Scientific, and Technical Services
Management of Companies and Enterprises
Administrative Support, Waste Management & Remediation Services
Arts, Entertainments, and Recreation
Accommodation and Food Services
Other: Agriculture, Forestry, Fishing & Hunting; Mining, Quarrying, and Oil &
Gas Extraction; Utilities; Retail Trade; Transportation & Warehousing;
Educational Services; Health Care and Social Assistance; Other Services; and
Public Administration
27
Example of Findings:
Dollars in 2010 Millions of GDP Generated by 1% Increases in the 3 connectivity variables shown
Airline
Domestic
Number of
Hubs
Nonstop
Industry
ServedAirlines
Departures
Domestic
Manufacturing
$158
$85
Wholesale Trade
$43
$51
Information
$24
Finance & Insurance
$151
$226
Real Estate, Rental & Leasing
$95
Professional Scientific & Technical Services
$57
$112
Management of Companies & Enterprises
$8
Administration & Support Waste Management Services
$11
Art, Entertainment & Recreation
$3
Accommodation & Food Services
$0.1
Other**
$3
Total
$201
$453
$374
** Other represents the aggregation of 9 economic sectors shown on Slide 27.
28
Number of
Airlines
Domestic
Nonstop
Departures
Manufacturing
$158
$85
Wholesale Trade
$43
$51
Industry
Information
Finance & Insurance
$151
Real Estate, Rental
& Leasing
$95
Professional
Scientific &
Technical Services
$57
Management of
Companies &
Enterprises
Airline
Two or More
Domestic
Hubs
Daily Nonstop
Nonstop
ServedDomestic
Destinations
Domestic
Flights
$123
$30
$226
$99
$42
$176
$49
$6
$23
$41
$34
$236
$153
$26
$7
$18
$16
$33
$23
$95
$51
$4
$20
Other**
$3
$272
$374
$38
$82
$0
$453
$180
$112
$3
$201
$64
$39
Accommodation &
Food Services
Total
$172
$19
$11
Art, Entertainment &
Recreation
$356
$24
$8
Administration &
Support Waste
Management
Services
Five or More
% World % World
International International
Daily Nonstop
GDP
GDP
Nonstop
Nonstop
Domestic
Served
Served
Departures Destinations
Flights
Nonstop
Daily
$686
$7
$14
$19
$100
$654
$119
$192
$683
Note: Impacts on each industry sector vary according to connectivity variable.
** Other represents the aggregation of 9 economic sectors shown on Slide 27.
29
$95
$68
$361
Variable
Jobs
Number of Airlines
Domestic Nonstop Departures
Airline Hubs Served-Domestic
Domestic Nonstop Destinations
Two or More Daily Nonstop Domestic Flights
Five or More Daily Nonstop Domestic Flights
International Nonstop Departures
International Nonstop Destinations
% of World GDP Served Nonstop
% of the World GDP Served Daily
% of the World GDP Served Two or More Daily
7,500
9,900
7,600
17,400
19,200
1,900
4,400
17,500
2,300
9,100
2,800
Labor
Income
$471
$614
$493
$963
$1,161
$106
$267
$949
$108
$517
$176
Output
$1,725
$2,025
$1,340
$3,030
$4,455
$336
$689
$3,240
$247
$1,291
$635
Value
Added
$794
$1,118
$831
$1,676
$2,135
$221
$429
$1,742
$156
$807
$291
Note: Jobs rounded to the nearest 100. Values in 2010 dollars (millions). Direct employment, labor income,
output and all spinoff impacts calculated using IMPLAN, LLC.
30
National extrapolation is for illustrative purposes
to show order of magnitude effects
Impacts based on 1% increase in the connectivity
variables below
Number of Airlines
Domestic Nonstop Departures
Airline Hubs Served-Domestic
Domestic Nonstop Destinations
Two or More Daily Nonstop Domestic Flights
Five or More Daily Nonstop Domestic Flights
International Nonstop Departures
International Nonstop Destinations
% of World GDP Served Nonstop
% of the World GDP Served Daily
% of the World GDP Served Two or More Daily
Mean Impacts of All Variables
Total Direct and
Multiplier Effects
Direct Effects
Jobs
Value Added
Jobs
Value Added
5,600
13,300
12,400
29,600
17,200
3,400
8,200
27,500
5,600
18,500
2,100
13,036
$862
$1,944
$1,605
$2,944
$2,806
$511
$824
$2,931
$292
$1,553
$305
$1,507
32,200
42,500
32,600
74,700
82,400
8,200
18,900
75,100
9,900
39,000
12,000
38,864
$3,407
$4,797
$3,566
$7,192
$9,161
$948
$1,841
$7,475
$669
$3,463
$1,249
$3,979
Note: Jobs rounded to the nearest 100. Values in 2010 dollars (millions). Calculations based on
the value added previously presented. The basis of the extrapolation is that the national GDP is
4.3 times the aggregate GDP of the 20 regions tested.
31
3

Air cargo differs significantly from passenger travel
 Key airports are different (cargo hubs, gateways)
 Shipping cost is more important than connectivity
 Current logistics network provides almost universal coverage

Approach
 Developed a time series analysis relating changes in air
cargo to changes in manufacturing and wholesale industry
productivity (for the years 1995, 2000, 2005, and 2010)
 Explaining changes to industry productivity reflected by
the amount of air cargo handled
32
Jobs
Labor
Income
Output
Value
Added
Direct Effect
1,200
$94 M
$490 M
$173 M
Total “Spinoff”
(multiplier) Effect
4,100
$228 M
$769 M
$411 M
Total Effect
5,300
$321 M
$1,259 M
$583 M
Impact Type
Note: Dollars in $2010 Millions
Note: Jobs rounded to the nearest 100. Values in 2010 dollars (millions). Direct employment, labor income, output
and all spinoff impacts calculated using IMPLAN, LLC.
33
National extrapolation is for illustrative purposes
to show order of magnitude effects
Direct Impacts for manufacturing and wholesale trade
industry sectors:
$742 million in direct value added
 5,100 direct jobs

Total impacts, including multiplier effects:


$2.5 billion in value added
23,000 jobs
34
4
 1% drop in airfare represents about $2 per domestic ticket and $7 per international
ticket
Market
Domestic
International
TOTAL
Change in Consumer Surplus
$506
$310
$815
Consumer surplus is the
difference between what
travelers are willing to
pay and what they
actually pay for air travel
 National economic impacts based on $815 million of additional consumer surplus
Impact Type
Direct Effect
Multiplier Effect
Total Effect
Jobs
Labor Income
Output
Value Added
1,400
4,400
5,800
$162
$223
$385
$553
$728
$1,281
$249
$408
$657
Note: Jobs are rounded to the nearest 100. Dollars are in 2010 value using
2012 national model from IMPLAN, LLC.
35
PART 3
36
The multiple approaches carried out in ACRP Project 0328 are complementary in understanding the economic
impacts of airports to the national economy:

The economic impact analysis is a snapshot of the
economic contribution of airports at a given moment

The dynamic analyses estimate how national economic
impacts of airports will change if:
(1) connectivity between airports and regions;
(2) air cargo tonnage; and/or
(3) the cost of airfare change.
37
Direct Impacts ($ values in millions)
Activity
Jobs
Labor Income
Output
Economic Impact of U.S. Airports
Changes in Economic Impacts Generated by:
1% Improvement of Connectivity Variables
1% Increase of Air Cargo Tonnage
1% Decrease in Air Fares
2,172,200
$147,642
$637,002
Value
Added
$247,424
13,000
5,100
1,400
$795
$403
$162
$3,043
$2,103
$553
$1,507
$742
$249
Total Impacts Including Direct plus Economic Multipliers ($ values as noted)
Labor
Value
Activity
Jobs
Output
Income
Added
Economic Impact of U.S. Airports
7,628,900 $452.5 Billion $1.6 Trillion $768.4 Billion
Changes in Economic Impacts Generated by:
1% Improvement of Connectivity Variables
38,900
$2.3 Billion $7.4 Billion $4.o Billion
1% Increase of Air Cargo Tonnage
22,700
$1.4 Billion $5.4 Billion $2.5 Billion
1% Decrease in Airfares
5,800
$0.4 Billion $1.3 Billion $0.7 Billion
Notes: Direct and total impacts of connectivity reflect the mean average of all 11 connectivity variables
All values are in 2010 dollars. Jobs are rounded to the nearest 100. Total impacts include estimates of direct, indirect, and induced
impact. National extrapolation for connectivity and cargo is for illustrative purposes to show order of magnitude effects.
Calculations used IMPLAN, LLC national model, Version 3, 2012.
38

Economic Development Research Group, Inc.

Dr. David Gillen, University of British Columbia

ICF International

Kramer aerotek

Mead & Hunt, Inc.
Cover photographs courtesy of Mead & Hunt
39
Part 4
40
Inputs: Labor, Capital,*
Materials, Services
AIRPORT
SERVICES
Generates Economic
Impacts
Passenger, Cargo, &
Aircraft Handled
For businesses, the sale of air
transportation services for
travel and cargo transport
support production and sales
of products and services by
U.S. companies and industries.
For personal travel, the final
product produced and sold is
transportation.
AIRLINE
SERVICES
Business Air Travel &
Air Cargo Shipments
INTERMEDIATE DEMAND
FOR AIR TRANSPORTATION
Air Transportation Input
Other Inputs
OTHER ECONOMIC
SECTORS
FINAL DEMAND FOR OTHER
GOODS & SERVICES
*Includes construction
Personal Air Travel
FINAL DEMAND FOR
AIR TRAVEL
42
Classification
Explanatory
Variables
Large Hubs
Connecting
enplanements
Medium and
Small Hubs
Domestic
commercial
operations at
medium hubs
Domestic
connecting
enplanements at
small hubs
Results
All else constant, an additional 5,000 domestic connecting
enplanements per year would be associated with an estimated
$2.3 million dollars of direct airport revenue.
All else constant, an additional 5,000 commercial operations at a
medium hub airport would generate approximately $2.1 million.
For small hub airports, an additional 100 domestic connecting
enplanements would yield an additional $1.97 million of revenue.
Regressions based on NPIAS data base of 3,330 airports, aviation facilities and
activities, regional socio-economic data and 1,013 economic impact studies
43
Classification
Non-hub
Primary
Airports
Explanatory
Variables
Results
Number of
domestic
enplanements;
All else constant, an additional 100 domestic enplanements at a
non-hub primary airport would be associated with a $0.13 million
increase in direct revenue. Additionally, a 1,000-foot increase in
Maximum runway runway length would be associated with a $0.66 million increase
in direct revenue.
length
A reliever airport with a 1,000-foot increased runway length
would, on average, tend to contribute to a $0.025 million increase
Non-primary Maximum runway
in direct revenues. This interpretation can also be applied to
Commercial
length at GA
reliever and commercial services airports by swapping out the
Service
airports, relievers parameter estimates. Additionally, general aviation airports
Airports,
and commercial experiencing an additional 1,000 general aviation (itinerant plus
Relievers and service airports
local) operations would see an additional $912 of direct revenue.
General
GA operations at It would be reasonable to expect direct revenues of $0.86 million
Aviation
dollars for a general aviation airport with a maximum airport
GA airports
Airports
runway length of 4,000 feet and 10,000 general aviation
operations.
44
Real GDP will increase if productivity in the
economy increases
 Production Function: Q  f (inputs, technology)
Multifactor Productivity (MFP) is the change in output(s) due to the change in inputs.
In this analysis, to estimate impacts of improved connectivity, output is Real GDP, and
inputs are changes in airport connectivity as well as other standard inputs such as labor.
To estimate impacts from increased air cargo, output is Real GDP, and inputs are
changes in enplaned and deplaned cargo tonnage.
45

Select a representative sample of 20 Regions (MSAs)
and 26 Airports

Assemble data on change in Multi-factor Productivity
(MFP) for each region in 1995, 2000, 2005 and 2010:
MFP By Industry
(BLS)
Regional Economic
Data (GRP,
investment, labor)
Nonstop Flight
Pattern (O-Ds,
frequency) for
sample airports
Among the 26 sample airports
and between the 26 airports &
15 major international markets
46
Calculated Elasticities of Airport MFP Analysis
Connectivity Measure
Two or More Daily Nonstop Domestic Flights
International Nonstop Destinations
Domestic Nonstop Destinations
Percent of the World GDP Served Daily
Five or More Daily Nonstop Domestic Flights
Airline Hubs Served-Domestic
International Nonstop Departures
Percent of the World GDP Served Nonstop
Domestic Nonstop Departures
Percent of the World GDP Served Twice or More Daily
Number of Airlines
Elasticity
(average)
0.0915
0.0375
0.0284
0.0259
0.0258
0.0254
0.0182
0.0169
0.0164
0.0161
0.0160
Rank
1
2
3
4
5
6
7
8
9
10
11
Relative
Weight
1.00
0.41
0.31
0.28
0.28
0.28
0.20
0.18
0.18
0.18
0.17
Interpretation: For every 1% increase of destinations served by Two or More Daily
Nonstop Domestic Flights, GDP will increase by .000915 on average (1% * .0915).
47

Change in price leads to change
in quantity demanded and in
consumer surplus

Change in spending on air
travel (measured by the
change in consumer surplus)
frees up money for other
consumption

The increased spending on
other goods and services
contributes to economic
growth
48
 1% drop in airfare represents about $2 per domestic ticket and $7 per international,
which is expected to create an aggregate of $991 million in passenger welfare
Market
Domestic
International
TOTAL
Change in Consumer Surplus Total Induced Air Travel Expenditure
$506
$671
$310
$320
$815
$991
 National economic impacts based on $991 million of induced travel expenditure
and $815 million of additional consumer surplus (dollars in millions)
Impact Type
Direct Effect
Multiplier Effect
Total Effect
Jobs
Labor Income
Output
Value Added
1,400
4,400
5,800
$162
$223
$385
$553
$728
$1,281
$249
$408
$657
Note: Jobs are rounded to the nearest 100. Values are in 2010 dollars using
2012 national model from IMPLAN, LLC.
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