As recently as 1998, the working-age share of food stamp households was at a low of 44 percent, before the dot-com bust and subsequent recessions in 2001 and 2007 pushed new enrollees into the program, according to the analysis by James Ziliak, director of the Center for Poverty Research at the University of Kentucky.
By education, about 28 percent of food stamp households are headed by a person with at least some college training, up from 8 percent in 1980. Among those with four-year college degrees, the share rose from 3 percent to 7 percent. High-school graduates head the bulk of food stamp households at 37 percent, up from 28 percent. In contrast, food stamp households headed by a high-school dropout have dropped by more than half, to 28 percent.
The shifts in food stamp participation come amid broader changes to the economy such as automation, globalization and outsourcing, which have polarized the job market. Many good-paying jobs in areas such as manufacturing have disappeared, shrinking the American middle class and bumping people with higher levels of education into lower-wage work.
An analysis Ziliak conducted for the AP finds that stagnant wages and income inequality play an increasing role in the growth of food stamp rolls.
Taking into account changing family structure, higher unemployment and policy expansions to the food stamp program, the analysis shows that stagnant wages and income inequality explained just 3.5 percent of the change in food stamp enrollment from 1980 to 2011. But from 2000 to 2011, wages and inequality accounted for 13 percent of the increase.
Several economists say food stamp rolls are likely to remain elevated for some time. Historically, there has been a lag before an improving unemployment rate leads to a substantial decline in food stamp rolls; the Congressional Budget Office has projected it could take 10 years.
"We do not expect income inequality stabilizing or declining in the absence of real wage growth or a significant reduction in unemployment and underemployment problems," said Ishwar Khatiwada, an economist for the Center for Labor Market Studies at Northeastern University who reviewed the Labor and Commerce departments' wage data.
Full- and part-time workers employed year-round saw the fastest growth in food stamp participation since 1980, making up 17 percent and 7 percent of households, respectively. In contrast, the share of food stamp households headed by an unemployed person has remained largely unchanged, at 53 percent. Part-year workers declined in food stamp share.
Associated Press writer Mary Clare Jalonick contributed to this report.