U.S. military deaths in Iraq have fallen sharply this year, a trend observers attribute to the effects of the U.S.-led surge offensive, better performance by Iraqi security forces, and civilian fatigue of war, CNN reported Tuesday. A CNN count of Pentagon figures showed that 309 U.S. troops in Iraq have died this year, including 222 in hostilities and 87 in non-hostile circumstances. The U.S. death toll has been far higher in past years. Last year, there were 906 deaths, and there were more than 800 deaths in 2006, 2005, and 2004. “It's no single effort. It's a combination of efforts,” Major General Jeffery Hammond, the commander of Multi-National Division in Baghdad, told CNN. “The people of Iraq are tired of violence, and they are assisting the security forces. The government is improving its ability to govern and to apply the rule of law.” The lower U.S. death toll comes as the United States prepares to withdraw its combat forces from population centers in 2009 and from all of Iraq by the end of 2011.