Demographic Dividend
Hong Kong Superstar actor Chow Yun Fat, two-time Oscar winner Hilary Swank, and blues legend Buddy Guy all share a common history: going from poor, rural backgrounds to reach the pinnacle of their fields in the big city.
Since the dawn of the industrial era, economic history has shown that when national economies transition from a primarily rural agrarian economy to an urban industrial one, birth rates shrink and economic productivity increases, especially as more people migrate from the former to the latter. The demographic dividend is an occurrence that happens when the economy grows concurrently with lower birth rate and longer mortality rates.
The fewer people adding to the population is outpaced by the growing labor force with increased productivity, which leads to extra income, i.e. the demographic dividend. This can come about via women joining the workforce in full- or part-time capacity, which is much easier in an urban than in a rural environment; more resources per child within smaller family units, greater GDP growth due to lower new population dependents, and more disposable income due to greater productivity and wages.