Take the wealthy countries as an example. In Western Europe, North America, and Japan, average per capita income increased from barely 100 euros per month in 1700 to more than 2,500 euros per month in 2012, a more than twentyfold increase.10 The increase in productivity, or output per hour worked, was even greater, because each person’s average working time decreased dramatically: as the developed countries grew wealthier, they decided to work less in order to allow for more free time (the work day grew shorter, vacations grew longer, and so on).
