Can a country get rich before it gets old? That is one of the fundamental questions in the studies of development. Each country goes through a demographic transition, in which a certain level of per capita income — associated with better natal care and more accessible health services — increases the birth rate and stimulates population growth, both of which come down after a few decades as behavioural patterns change and fertility declines. This interim period of fast population growth is one in which countries have a favourable dependency ratio; the working-age population is large, when compared to those who

)