Unintended consequences. Nice analysis, Umair. It's interesting isn't it, that usually when we're thinking about human population data, dropping reproduction rates are seen as an indicator of economic development. The bloodless explanation that you'll see repeated in texts on development is that for poor people in developing countries having large numbers of children is a way of hedging bets and spreading risk exposure, also maybe as a way of generating cheap labour. We're not used to the idea that low fertility in "rich" countries might be a sign of wealth inequality and economic stagnation. If the poor stop having babies who will service the needs of the hyper-rich?