"This report collects statistics from a variety of sources on casualties sustained during Operation Enduring Freedom (OEF), which began on October 7, 2001, and is ongoing. [...] Casualty data of U.S. military forces are compiled by the U.S. Department of Defense (DOD), as tallied from the agency's press releases. Also included are statistics on those wounded but not killed. Statistics may be revised as circumstances are investigated and as records are processed through the U.S. military's casualty system."
CRS Report for Congress, R41084