In 1870, between 70 and 80 percent of the population of the United States still lived and worked on farms. By 2010, this proportion had dwindled to less than 1 percent of the population. Yet as a result of the mechanization of agriculture made possible by the internal combustion engine, the 1 percent of agricultural workers remaining in the United States produce more food than is consumed by the remaining 99 percent of the population.
