The Congressional Budget Office's report, scheduled for release Tuesday, indicates one of every five dollars spent on the war in Iraq went to contractors for the U.S. military and other government agencies, The New York Times reported.

The Defense Department's dependence on outside contractors in Iraq -- about 180,000 privately contracted people work in the Mideast country -- is proportionately larger than in any previous conflict, fueling charges that the practice has led to overbilling and fraud, and places U.S. troops in harm's way, the Times said.

The report found that from 2003-2007 the government awarded contracts in Iraq worth about $85 billion. Since the Bush administration awards contracts now at a rate of $15 billion to $20 billion a year, the report said contracting costs will top the $100 billion mark before the end of 2008, people familiar with the report said.

"This is the first war that the United States has fought where so many of the people and resources involved aren't of the military, but from contractors," said Charles Tiefer, a professor of government contracting at the University of Baltimore Law School and a member of an independent commission Congress created to study contracting in Iraq and Afghanistan.