Read population pyramids

Grade 9 Social Studies Worksheet - Building Confidence

Circle the best answer.

1. Read this first

   Use this

   Card A, three population pyramids, 2023 (UN estimates, World Bank), in words. Niger: a very wide base that narrows quickly; 47.0% of people are aged 0–14 and 2.6% are 65 or older. Japan: a narrow base and a wide top; 11.6% are aged 0–14 and 29.6% are 65 or older. United States: closer to a column; 17.6% are aged 0–14 and 17.4% are 65 or older. Card B, key and notes: each bar is an age group, youngest at the bottom; males are on the left and females on the right; bar length is the share of the population. A broad base means a high share of young people, which suggests a high birth rate. An expansive pyramid has a wide base, a constrictive pyramid a narrow base, and a stationary pyramid about the same width from bottom to top; in a stationary population, births and deaths roughly balance. The age shares of a country add to 100%.

2. 1.

   Ren reads Card A. Which pyramid has the widest base, and what does that suggest?

   • Niger's: 47.0% are aged 0–14, far more than the others, which suggests a high birth rate there
   • The United States': a column is wide at the bottom, so it has the widest base of the three
   • Japan's: its wide top shows many young people, which suggests a high birth rate there as well
   • Niger's: 47.0% are aged 0–14, which shows its birth rate will stay high in the years to come
3. 2.

   Japan's pyramid has a narrow base and a wide top. What type is it, and why, Tala asks?

   • Stationary: a base and a top of different widths are what make a pyramid stationary and steady
   • Expansive: a wide top means the population is growing quickly, because many older people are alive
   • Constrictive: a narrow base means few young people, 11.6%, next to many older people, 29.6%
   • Expansive: 29.6% is a larger share than 11.6%, and a larger share at either end makes it expansive
4. 3.

   The United States pyramid is closer to a column, with 17.6% aged 0–14 and 17.4% aged 65+. Which type is it, Zee asks?

   • Constrictive: the older share, 17.4%, is large, so the top is wider than the base
   • It is not any of the three types, since a column has no wide part and so has no type
   • Stationary: the base and top are about the same width, at 17.6% and 17.4%, so it is close to a column
   • Expansive: 17.6% aged 0–14 is a larger share than Japan's 11.6%, so its base is wide, as Niger's is
5. 4.

   In Japan, how do the shares aged 65+ and aged 0–14 compare, using Card A, Bo asks?

   • Young people outnumber older people, since the young belong to the base of the pyramid and the base is wide
   • Older people outnumber young people about 2.5 to 1, since 29.6% is about 2.5 times 11.6%
   • Older people outnumber young people about 5 to 1, since 29.6 is about 5 times the 6 that is left over
   • They are about equal, since both are shares of one population and the two shares must therefore balance
6. 5.

   What share of Niger's people are aged 15–64, using Card A and the note that shares add to 100%, Esme asks?

   • About 5%, since 47.0 minus 2.6 minus the rest leaves a small share in the middle ages
   • About 50%, since the three shares add to 100 and 100 minus 47.0 minus 2.6 is 50.4
   • About 53%, since 100 minus 47 is the share aged 15–64 and the older ones are counted among them
   • About 49.6%, since 47.0 plus 2.6 is the share that is aged 15–64 and the others are children
7. 6.

   Why does a wide base suggest a high birth rate, Jun asks?

   • A wide base means many older people are alive, and their long lives raise the number of births
   • A wide base means each woman has the same number of children, and the births per woman follow from it
   • A wide base means many young people, and they were born in recent years, so births have been high
   • A wide base means children are counted twice, so the birth rate is double what it would otherwise be
8. 7.

   Which type is Niger's pyramid, with a very wide base that narrows quickly, Kira asks?

   • Expansive, since the older share is large, 2.6%, and a larger top makes it expansive in shape
   • Stationary, since the narrowing is steady from bottom to top and so is the same shape throughout
   • Constrictive, since a base that narrows quickly is a constricted base
   • Expansive, since Niger's base is very wide and a pyramid with a wide base is called expansive
9. 8.

   Which list puts the three countries in order from the widest base to the narrowest, using Card A, Milo asks?

   • Niger first at 47.0%, then the United States at 17.6%, then Japan at 11.6%
   • Niger, then Japan, then the United States, since the United States is nearly a column and so is narrowest
   • The United States, then Niger, then Japan, since a column is wide at the bottom and so beats a pyramid
   • Japan, then the United States, then Niger, since Japan's pyramid is widest at the top
10. 9.

    Which claim about Niger is best supported by Cards A and B, Noah asks?

    • Its wide base suggests a high birth rate, though the pyramid does not give the number of births per woman
    • Niger's population is growing by 47% a year, since 47.0% of people are children and children are growth
    • Niger has 47 births for each 100 women, since 47.0% is the share aged 0–14 in the pyramid
    • Niger's birth rate is lower than Japan's, since Niger's pyramid has a shorter top than Japan's
11. 10.

    Which country has fewer young people than older people, using Card A, Pia asks?

    • Both Japan and the United States, since each has a top that is at least as wide as its base
    • The United States, since 17.4% aged 65+ is almost as much as the 17.6% aged 0–14 and so is larger
    • Japan, with 11.6% aged 0–14 against 29.6% aged 65+, so its older people outnumber its young
    • Niger, since just 2.6% of its people are aged 65+ and that small share is a narrow top