Socio-economic class comes into this strongly as well.

In a number of the countries noted, the chances (sorry to use the word, statistics would make this the probabilities) are those from certain middle and elite classes were registered properly in the births, deaths system at its earlier stages of development.

Would be very interesting to look at spatial distribution of affirmed ages within a country given the diversity of conditions found/experienced across a number of the countries noted.

Anecdotal point - The Economist was stopped from holding an event in Kenya some years ago when noting the differential life expectancy of men and women in different places across the country. This was tied to the cronyism around the Moi regime and the starvation of development resources going to certain regions. These regions were already disadvantaged due to the centripetal forces apparent from colonial era developments of nodes, trade and power underpinning how politics latter developed. Countries gained independence but the vestiges of power founded in economic extraction and social manipulation create lasting impacts on the quality of living and the longevity of life.