Fun with Population Pyramids
I was scouring the web looking for fact ideas as we all are known to do, and I stumbled upon an interesting, if short, fact — the African country of Niger has a rapidly growing population. So rapid, in fact, that in 2015, more than 49% of the population was under the age of 15. Even more striking than this is the fact that more than 25% of the population was under the age of 5. This made me think about population pyramids, and how much I love them. So today, we’ll do a little world tour of population pyramids that reflect many interesting historical and sociological phenomena.
For reference, there are a few types of populations pyramids, depicted below. They’re quite simple charts, but are useful quick depictions of population trends — and if you find an interesting one, often a unique reflection of a country.
The convexity of the pyramid toward the top can be viewed as a measure of life expectancy/quality of long-term healthcare in the country. The more curvature towards the axis, the worse off the country is on these dimensions. On the other hand, the convexity towards the bottom is a measure of the rate of reproduction in the country. So back to this famous Niger pyramid.
As you can see, this is a pretty typical pyramid of a Stage 1 country. The degree to which it is though it pretty startling — the average woman bears 7.1 children. Average. Compare this pyramid to that of the US.
While more typical, there are still some interesting aspects here. The bulge around ages 50–70 is illustrative of the impact of baby boomers. Additionally, the top of graph convexity shows a pretty stark difference in aging/death between males and females. For example, there are ~40% more women in the 80–84 group than men. This jumps to 60% more women in the 85–89 group. If you look at this longitudinally, this means that 37.5% of men pass away in the transition from 80–84 to 85–89, versus only 27.3% of women. Stay safe, boyos. I’m tryna chill with y’all until the top of the pyramid.
There are also some good examples of countries in Stage 4, countries beset with contracting populations. Spain and Japan are notable examples — look how funky these pyramids are. These people need to get busy a little more.
Another super interesting one is China. As you know, China enacted a one-child policy in 1977. If there was an impact from that, you would see that in the 35–39 age group and younger in the 2015 data.
As you can see, this is exactly the age group affected, and it creates a odd “notch-like”shape in the pyramid. This would also imply that the impact of this policy was most powerful from 1977–1987, with the effect tapering off drastically from 1987–1992.
Another, much darker side effect of this policy relates to Chinese parents’ preference for male vs. female children. We’ve all heard anecdotal evidence of the particularly heinous ways that this manifested itself (and the long-term sociological problems it has created), but the impact on population is clear — there were 1.26 male children born for every 1 female child in the early 1980’s. Some of this effect has rounded off in this population pyramid, as young males are more likely to emigrate (especially if they’re one of the 30 million men that can’t find a wife because of the population imbalance). Still, there are 6% more men than women ages 25–39.
Speaking of the impact of immigration, this shows up in unique ways on some countries’ population pyramids. Take Nepal, for example. The relative paucity of jobs here makes young Nepalese people, primarily men, apt to emigrate to neighboring countries to find work.
Look at how wonky and asymmetric this pyramid is. It looks like someone (India?) took a nice bite out of the left side of the pyramid around 25–39. This India hypothesis seems to also be borne out in the data.
On the other hand, some countries’ pyramids are blown up by immigration. Take the Saudi Arabia or the UAE for example — this shit is crazy.
Anyway, hope y’all enjoyed this foray into the beautiful world of population pyramids.
