E xercise for C hart The Age Group ‘pyramid’ shown in Chart provides a much more detailed version of the kind of age grouped data presented in Table . Here, data are shown separately for males (on the left side) and females (on the right side) with the relevant five-year age group in the middle. Looking at the horizontal bars (including both males and females in a particular age group) gives you a visual sense of the age structure of the population. The age groups begin from the - years group at the bottom of the pyramid and go on to the years and above age group at the top.
There are four different pyramids for the decennial census years of , , and the estimates for . The pyramid for shows the estimated future size of the relevant age groups based on data on the past rates of growth of each age group. Such estimates are also called ‘projections’. These pyramids show you the effect of a gradual fall in the birth rate and rise in the life expectancy.
As more and more people begin to live to an older age, the top of the pyramid grows wider. As relatively fewer new births take place, the bottom of the pyramid grows narrower. But the birth rate is slow to fall, so the bottom doesn’t change much between and . The middle of the pyramid grows wider and wider as its share of the total population increases.
This creates a ‘bulge’ in the middle age groups that is clearly visible in the pyramid for . This is what is refered to as the ‘demographic dividend’ which will be discussed later in this chapter. Study this chart carefully. With the help of your teacher, try to trace what happens to the new-born generation of (the – age group) as it moves up the pyramid in succesive years.
Where will the – age group of be located in the pyramids for the later years ? Where – in which age group – is the widest part of the pyramid as you move from to ? What do you think the shape of the pyramid might be in the year and ?