单项选择题

Historians may well look back on the 1980s in the United States as a time of rising affluence side by side with rising poverty. The growth in affluence is attributable to an increase in professional and technical jobs, along with more two career couples whose combined incomes provide a "comfortable living". Yet simultaneously, the nation’s poverty rate rose between 1973 and 1983 from 11.1 percent of the population to 15.2, or by well over a third. Although the poverty rate declined somewhat after 1983, it was still held at 13.5 percent in 1987, comprising a population of 32.5 million Americans.
The definition of poverty is a matter of debate. In 1795, a group of English magistrates decided that a minimum income should be "the cost of a gallon loaf of bread, multiplied by three, plus an allowance for each dependent". Today the Census Bureau defines the threshold of poverty in the United States as the minimum amount of money that families need to purchase a nutritionally adequate diet, assuming they use one third of their income for food. Using this definition, roughly half the American population was poor in the aftermath of the Great Depression of the 1930s. By 1950, the proportion of the poor had fallen to 30 percent and by 1964, to 20 percent. With the adoption of the Johnson administration’s antipoverty programs, the poverty rate dropped to 12 percent in 1969. But since then, it has stopped falling. Liberals contend that the poverty line is too low because it fails to take into account changes in the standard of living. Conservatives say that it is too high because the poor receive other forms of public assistance, including food stamps, public housing subsidies, and health care.
How many people are there in the United States in 1987