By popular demand, Wolfram|Alpha recently expanded population data for most of the world’s countries, based in part on statistics from the United Nations Population Division. Populations are shaped by factors such as disease, war, genocide, and famine as well as more benign phenomena such as immigration. One of the more common user requests in this area has been to support queries like “China population distribution”, which now returns an age pyramid and detailed table of population by age and sex:
Here, Wolfram|Alpha computes that this age group represented about 6.5% of the total population in 2010. If you click the “Show history” button in the population fraction pod, you’ll also see that this fraction has been mostly in decline since 1950. What might China look like 20 years from now? Enter “China age distribution 2030” and you’ll see that, relative to the middle-aged, the youngest population is likely to represent an even smaller fraction of total population.
You can also compare multiple countries: try “US, China, India population fraction age 65 in 2030” to see how rapidly these countries are aging.
There is a lot of history to explore. Let us know if you spot any other interesting trends in this data.