## The Indian age pyramid

After some smoothing of the data from the Census Bureau of India on the age distribution of the Indian population, one sees some interesting features.

First, there is a definite bulge in the population at the age of 10. In other words, the happy news is that the *Indian baby boom* ended at the beginning of the millennium. If one separates out the data on urban and rural populations, this trend is seen in both. On examining this separated data, it seems possible that this decline in the growth rate began more than a decade ago in the urban population.

Second, one can see a roughly exponential fall in the population between the ages of 21 and 60. This exponential sets a “half life” for an average Indian. This turns out to be about 27 years. In other words, an Indian who survives to age 20 can expect to survive till age 55. This corresponds to a very high probability of an adult dying at any age: almost 2.5% in one year. Beyond age 55 this the survival rate decreases even more rapidly. The “half life” of women is a little higher than that of men.

This brings us to the third observation. There is a marked excess of males over females at all ages up to about 50. Among older people, there is a small excess of females over males, as in the rest of the world. The net excess of males over females is 35 millions. When adjusted for the longer half life of women, the number of missing women is 211 million. This very crude estimate bears out the findings reported by Anderson and Roy.

[…] Note that the population pyramid turns over and narrows at the base. If ages of babies are not misreported widely, then this means that the rate of growth of population has slowed significantly in the last 5 years. This seems to have happened in the rural as well as the urban population. More about this here. […]

How many people lie about their age? | Karela FrySeptember 15, 2013 at 5:13 pm

[…] The histogram above should put these numbers into perspective. There are about 80 million Indians in the age range between 18 and 22. If we want to build a technological society like Japan’s or South Korea’s, all of them should go to college. If the teacher-taught ratio is to be 1:15, then we need to hire 5.3 million college teachers. Compare this to 1.5 lakh teachers today: the number of teachers has to be be multiplied by 35 or so. The fraction of the GDP which is spent on higher education will have to go up by a similar factor. […]

Higher education by numbers | Karela FrySeptember 24, 2013 at 11:39 am