The number of Americans fighting off hunger stayed level last year, though food insecurity rates remain the highest they have been since the federal government began keeping track 15 years ago, a Department of Agriculture report released Monday found.About 14.7 percent of U.S. households were "food insecure" in 2009, meaning they had difficulty feeding one or more of their members at some point last year due to a lack of financial resources, according to the report.That equates to 17.4 million households total, or roughly 45 million people.This year's rate marked a slight increase in percentage from 2008, when 14.6 percent of American households had trouble putting food on the table.The situation was especially dire for more than one-third of those households -- 6.8 million total, equating to 5.7 percent of all U.S. households -- that the report's four authors classified as having "very low food security."