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SKILLS
SKILLS
Working with Population Pyramids
M1 Elements of a population pyramid
A population pyramid is a common demographic chart. It graphically displays a population’s age structure and sex composition.
Set-up of a population pyramid
Bar graphs are a handy way to illustrate numbers. With a population pyramid demographic data (M2) are often presented as two
back-to-back horizontal bar charts.
Males are plotted on the left and females on
the right, with a vertical axis showing age
ascending in five-year intervals (five-year cohorts), from the youngest upwards to the
oldest. The horizontal axis shows either the
population of the cohorts in millions or in per
cent. Thus each horizontal bar represents the
size of an age-sex cohort as a share of the
total population.
Interpreting a population pyramid
When drawn as a population pyramid, age
distribution can hint at patterns of growth.
A bottom heavy pyramid suggests high birth
rates, falling or stable death rates, and the
potential for rapid population growth. This
type is called an expansive pyramid. A top
heavy pyramid suggests negative population
growth that might be due to different factors, including low birth rates or an increased
emigration of people especially from the
younger cohorts. This type is called a constrictive pyramid.
The third type, a stationary pyramid, shows
roughly equal numbers of people in all cohorts, with a tapering towards the older
age.
The sex ratio frequently varies in different
cohorts, with the top of the pyramid often
showing that females comprise a majority.
This is because females typically outlive males.
Pyramids also show the relationship between
the dependent population (under 20 and over
64 years) and the economically productive
population (between 20–64 years).
Model text
The population pyramid of Germany (2007)
shows a narrow base reflecting a low birth
rate. The wide middle part shows that the
economically productive population is bigger
than the dependent population. The top of
the population pyramid is characteristic of a
country with a high life expectancy.
The sex ratio is mostly even or shows a slightsurplus of the female population in the cohorts from 70 years on. This reflects the higher life expectancy of the female population.
All in all, this population pyramid is a mixture
of two types, a stationary and a constrictive
pyramid. For the future it shows the problem
that the share of the economically productive
population will markedly decrease.
The shape of a population pyramid shows the
development status of a country – there is a
distinct difference between the pyramids of a
less economically developed country (LEDC),
e. g. Niger, and a more economically developed country (MEDC), e. g. France (M3).
Country or area/
year/ age
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Population
both sexes
Population
male
Population
female
Per cent
both sexes
Per cent
male
Per cent
female
82,400,996
40,478,053
41,922,943
100
100
100
0– 4
3,489,184
1,790,721
1,698,463
4
4
4
5– 9
3,896,719
1,999,317
1,897,402
4
4
4
10–14
4,099,194
2,104,686
1,994,508
5
5
4
15–19
4,744,341
2,434,380
2,309,961
5
6
5
20–24
4,758,914
2,444,354
2,314,560
5
6
5
25–29
4,800,835
2,467,411
2,333,424
5
6
5
30–34
4,706,691
2,240,071
2,286,620
5
6
5
35–39
6,325,862
3,255,284
3,070,578
7
8
7
40–44
7,306,422
3,767,858
3,538,564
8
9
8
45–49
6,657,608
3,400,387
3,257,221
8
8
7
50–54
5,765,938
2,904,702
2,861,236
7
7
6
55–59
5,209,151
2,592,984
2,616,167
6
6
6
60–64
4,325,817
2,123,926
2,201,891
5
5
5
65–69
5,363,001
2,563,473
2,799,528
6
6
6
70–74
4,061,797
1,851,039
2,210,758
4
4
5
75–79
3,015,014
1,255,543
1,759,471
3
3
4
80 +
3,874,508
1,101,917
2,772,591
4
2
6
Germany (2007)
Total, all ages
Source: U.S. Census Bureau, International Data Base (all data calculated; data in per cent rounded)
M2 Population of Germany by age and sex
M3 Population pyramids of a less economically developed country (LEDC) and a more economically
developed country (MEDC)