WASHINGTON – U.S. soldiers had higher morale and suffered fewer mental health problems in Afghanistan last year as they handed off more duties to Afghans and saw less combat themselves, according to a report released Monday.

The Army report was drawn from a battlefield survey and interviews in June and July. It was the ninth time since the practice started in 2003 in Iraq that the service had sent a team of mental health experts to the field of war to measure soldier mental health and assess care.

The report said rates of soldiers with depression, anxiety and acute stress — as well as tendencies toward suicide — were lower than in the most recent previous surveys.

In a survey of nearly 900 soldiers, 20.2 percent said last year that their morale was high or very high, compared with 14.7 percent and 16.3 percent in 2012 and 2010, respectively.

During those earlier survey years, there were more U.S. troops in Afghanistan — 100,000 at the height of the surge that started in 2010. Now, there are 34,000 U.S. troops.

"The differences in individual morale in 2013 relative to 2010 and 2012 may reflect differences in combat experiences during those two years … years with the highest combat experience levels" of the war, said the report by the office of the Army surgeon general.

Last year, the U.S.-led international forces in Afghanistan suffered the lowest number of casualties in the past six years, while Afghan security forces saw their casualties mount as they took the lead in the 12-year war against the Taliban. According to an Associated Press tally, U.S. deaths fell to 118 from 297 in 2012, while casualties among Afghan army and police rose to 2,767, up from 1,870 the year before.

The number of soldiers who thought they would be better off dead or had considered hurting themselves was 8.5 percent last year compared with 9 percent and 13 percent in 2012 and 2010, respectively.

The rate of troops who met the criteria for acute stress was 8.5 percent last year compared with 11.2 percent and 14.9 percent in 2012 and 2010, respectively. For depression, it was 3.1 percent last year, compared with 3.8 percent and 6.5 percent in 2012 and 2010.

Almost 25 percent of soldiers had high or very high concern about not getting enough sleep. Though that was the lowest rate in the last four surveys, more than 18 percent said they fell asleep on guard duty and 47 percent slept while riding in convoys. About 12.5 percent blamed lack of sleep for an accident or mistake.