From Alon Levy in comments:
Every human development report has a table of aid donors and recipients. The latest one says that among the 22 donor countries, the US ranks 21st in aid as a percentage of GDP and 18th in aid per capita. Although the US spends more than any other country in absolute terms, it spends somewhat less than the combination of France, Germany, and Britain, which has two thirds its population and half its GDP.
