Federal welfare spending has grown by 32 percent over the past four years, fattened by President Obama’s stimulus spending and swelled by a growing number of Americans whose recession-depleted incomes now qualify them for public assistance, according to numbers released Thursday.

Federal spending on more than 80 low-income assistance programs reached $746 billion in 2011, and state spending on those programs brought the total to $1.03 trillion, according to figures from the Congressional Research Service and the Senate Budget Committee.

That makes welfare the single biggest chunk of federal spending — topping Social Security and basic defense spending.

Sen. Jeff Sessions, the ranking Republican on the Budget Committee who requested the Congressional Research Service report, said the numbers underscore a fundamental shift in welfare, which he said has moved from being a Band-Aid and toward a more permanent crutch.