Sen. Kent Conrad (D-N.D.), chairman of the Senate Budget Committee
"This chart demonstrates that revenue has to be part of the solution to the deficit. It shows that the last five times the budget was in surplus (in 1969, 1998, 1999, 2000, and 2001), revenue was near 20 percent of GDP. Revenue is now at 15.4 percent of GDP, near its lowest level in 60 years."
Sources: OMB, CBO