April 2,2008: After September 11, 2001, the U.S. began sending troops overseas to deal with terrorist threats to the United States. By the end of 2001, 51,000 troops were so deployed. Most of them (57 percent) were from the navy. Another 27 percent were air force. By the end of 2002, there were 77,000 troops overseas on counter-terror missions. The navy (39 percent) and air force (34 percent) continued to be the major players. But in 2003, Iraq was invaded. That year, there were 220,000 U.S. troops overseas, and half of them (on average) were army (the marines were another 15 percent). In 2004, the average number of troops overseas on counter-terrorism duty dipped to 216,000, but the army was two-thirds of that. In 2005, as the Sunni Arab terror campaign in Iraq intensified, the average number of U.S. troops overseas went to 245,000 (64 percent army, 10 percent marines). In 2006, there were 247,000 troops over there (63 percent army, 13 percent marines). Last year, the total was 256,000 (61 percent army, 13 percent marines). In the last two years, about ten percent of the troops overseas are navy and air force personnel serving on the ground in direct support of the army and marines.