The US Army's desertion rate dropped sharply in the past year to the lowest point since the Vietnam war, a welcome relief which experts believe is thanks to a sputtering economy, better recruits and the drawdown of US forces in Iraq.

"The Army right now is in a place where it can be very selective of the soldiers that it recruits," said Pentagon spokesman Lieutenant Colonel Steve Warren "and because of that we are bringing into the Army the very best that America has to offer."

Despite a patriotic surge in the wake of the terrorist attacks of September 11, 2001, the Army had trouble keeping its ranks filled amid the intense pressures of the wars in Afghanistan and Iraq.

The desertion rate actually jumped in the wake of the attacks, with 4,399 soldiers fleeing their posts in 2001, and began to rise as Iraq unraveled in 2005 and 2006.

It peaked during the 2007 surge to 4,698 troops, which was just under one percent of the service rolls and the Army's highest desertion rate since records became available in 1970.

A 2002 Army report found that the number of deserters and AWOL soldiers usually rises in wartime as more demands are placed on troops and enlistment standards are lowered -- something that happened as Iraq careened into chaos.

Those deserting also rose amid programs like "stop-loss," an Army program that kept thousands of GIs on active duty after their commitment expired during part of the Iraq war.

Another factor could be that the Army was forced to loosen its recruitment standards by expanding the admission of felons, high school drop outs and recruits with the lowest scores.

That changed in 2008 when the US economy fell into the deepest economic downturn in decades.

Just 1,202 soldiers were dropped from the service's rolls after being labeled deserters in fiscal year 2010, which ended September 30. The number is down by nearly third from the 2009 total of 1,717 troops and is the lowest percentage for desertion since 1973.

While the economy plays a role in driving recruits and troop retention, desertion is often more complex and personal, said Bernard Trainor, who led Marine recruiting in the Northeast from 1974-1976 and co-wrote an acclaimed history of the Iraq invasion.

"The economy has got to be a player, but it's not the 100-percent factor, and I don't know what the other percentage is because there's a lot of other motivations that attract or drive people into the military," Trainor told AFP.

"Therefore, with them being more selective, they're getting a better-quality guy and that automatically is going to lower the dissatisfaction rate and, with it, the desertion rate."

University of Maryland military sociologist David Segal studied the phenomenon with researcher D. Bruce Bell in the 1970s.

He said soldiers deserting during Vietnam generally did so because of financial or family problems, or because they could not adjust to life in the military.

Vietnam's bitter legacy and the early years of a volunteer military led to a force beset by drug abuse, racial strife and poor-quality trainees.

Evidence of trouble in the ranks was borne out virtually every week as FBI agents brought Marine deserters to Trainor's Garden City, New Jersey headquarters. "We found the Vietnam-era deserters to look like World War II and Korean War deserters," he said. "They tended to be young, unmarried, less well educated, in lower mental-aptitude categories, in less-skilled military occupations, and in the lowest pay grades."

It was not uncommon for the wayward troops to say they ran from their posts because of fears over violence -- and even being killed by other Marines.

"Most of the deserters were the bums, the slime, but there was a significant percentage of people that deserted at that time because the quality of life and the leadership was so bad in their perception, and for them, it was a rational decision," Trainor told AFP.

Today's soldiers are older, better educated, and more likely to be married and holding more-skilled occupations than their draftee and early-volunteer force counterparts, said Segal, the military sociologist.

The Army also has an array of programs to help soldiers and their families deal with financial and social issues that did not exist during the Vietnam era.

The Army classifies soldiers as deserters after they have been absent without leave for a month. The bulk are typically lower-ranking GIs who have not finished their first year of duty.

Soldiers deserting in times of war can be executed. But a review of Army judicial records shows that just 1,213 desertion cases were tried from 1990 to 2007, averaging slightly more than 71 a year.

Over that time, at least 43,810 deserted.

"The normal way you get rid of them is with an administrative separation called a Chapter 10, a discharge in lieu of court-martial," said one-time Army lawyer Geoffrey Corn, a professor at South Texas College of Law in Houston.

"It's a plea agreement."