The world's output of work

The total amount of work done in the world may be computed if reasonable general assumptions are made. Human labor corresponds to about one-eighth of the total, whereas mechanical work done by the utilization of the energy in coal corresponds to two-thirds. The work done by petroleum greatly exceeds that done by water power which is less than human work. The per capita work done in the different countries of the world varies widely, ranging from 13 horsepower-hours daily per capita in the United States to less than one-half horsepower-hour in India and China. A general relationship between work done per capita and economic well-being is observable; but a precise correlation is not yet possible.