The problem isn’t just absolute population, but relative population. How many working people are there and how many dependents? What’s the ratio? And how many

The problem isn’t just absolute population, but relative population. How many working people are there and how many dependents? What’s the ratio? And how many of the dependents will “graduate” to productivity (children v elderly)? A geriatric society with a large number of elderly is very different from a society with a demographic dividend from fewer children.