According to the 2014 version of a report that the Department of Health and Human Services is required by law to issue annually, the percentage of Americans on welfare in 2011 was the highest yet calculated. The data for 2011 is the most recent in the report.
HHS has calculated the percentage of all persons in the United States who live in families that receive “welfare” going back to fiscal 1993. It has not calculated a percentage for years prior to that.
As defined in the report (“Welfare Indicators and Risk Factors”), a welfare recipient is any person living in a family where someone received benefits from any of just three programs—Temporary Assistance to Needy Families (formerly Aid to Families With Dependent Children), Supplemental Security Income, and the Supplemental Nutrition Assistance Program (or food stamps).