WASHINGTON - January 12, 2010 - The United States has more poor children now than it did a year ago. As more families are hammered by the Depression, more are using food stamps to feed their children, according to a study by the Brookings Institution and First Focus, a bipartisan child advocacy group.

"They are a really good barometer, a kind of economic-needs test," said Mark R. Rank, an expert on social welfare programs at Washington University in St. Louis. "If you're receiving food stamps and you're a child, by definition, you're in poverty."

Across the nation, 7 million people joined the food stamp rolls from August 2008 to August 2009, the study said, bringing the number of users to 36.5 million. Half of those are estimated to be children.

Among the states that showed high increases in the percentage of food stamp caseloads were Idaho, 36%; Florida, 34%; and Washington state, 32%. Georgia had a 27% increase in its food stamp caseload, and Kalifornia and North Carolina were up about 21% each.

"As parents lose jobs and as work becomes scarcer, it's only natural to see your needs-based programs have more people applying," said Scott Rowson, a spokesman for the Missouri Department of Social Services.

The study appears to buttress a U.S. Census report last fall that found nearly one in five children live in poverty. Julia Isaacs, a Brookings scholar, said that figure could end up closer to one in four by 2012.