the u.s. national debt grew significantly from 2001 to 2009, both in dollar terms and relative to the size of the economy (gdp), due to a combination of tax cuts, wars and recessions. measured for fiscal years 2001–2008, federal spending under president bush averaged 19.0% of gdp, just below his predecessor president bill clinton at 19.2% gdp, although tax receipts were substantially lower at 17.1% gdp versus 18.4% gdp. income tax revenues averaged 7.7% gdp under bush, versus 8.5% gdp under clinton. the sizable national debt increases during his administration represented a reversal from a sizable surplus projection by the congressional budget office just prior to his taking office.