According to the report:
In 2004, 36.6 million people—or 12.6 percent of the U.S. population—were poor. The “poverty gap”—the amount of additional income required to remove all Americans from poverty—was $105.6 billion. Poverty rates were highest for African Americans, Hispanics, women, and persons under 25. Without government benefits, 61 million people would be poor. Social Security and other social insurance programs remove 21 million people from poverty. Means tested programs remove 3 million people from poverty. If food and housing assistance were counted as income for poverty purposes, an additional 7.6 million people would be counted as not poor.
Full report: Poverty Facts, 2004