From the Monthly Budget Review: Fiscal Year 2010 (October 7, 2010):

CBO estimates that the federal budget deficit was slightly less than $1.3 trillion in fiscal year 2010 and $125 billion less than the shortfall recorded in 2009. The 2010 deficit was equal to 8.9 percent of gross domestic product (GDP), CBO estimates, down from 10.0 percent in 2009 (based on the most current estimate of GDP). The 2010 deficit was the second highest shortfall?and 2009 the highest?since 1945, relative to the size of the economy. CBO?s deficit estimate is based on data from the Daily Treasury Statements and CBO?s projections; the Treasury Department will report the actual deficit for fiscal year 2010 later this month. (Emphasis added)