WASHINGTON — The divorce rate in the armed forces held steady last year at 3.3 percent, a surprising finding given the stress that marriages are under during persistent wars in Iraq and Afghanistan.

Some veterans questioned whether the figure, reported by the Pentagon, presents an accurate picture. But defense officials credited efforts in recent years to support couples enduring uncommonly long separations and other hardships because of those wars.

The divorce rate represented more than 25,000 failed marriages among the nearly 755,000 married active duty troops in all military branches between Oct. 1, 2006, and Oct. 1, 2007, according to statistics provided to The Associated Press.

The Defense Department data showed that the Army, the service with the largest number of troops in Iraq and Afghanistan, had a rate of 3.2 percent, unchanged from the previous year. That amounted to 8,748 divorces among the approximately 275,000 married soldiers.

Last year was the deadliest yet for U.S. troops in the wars. In addition, Army couples had to cope with extended separations because tours of duty lasted 15 months rather than 12 months.

Those longer deployments and multiple tours required of many troops have been widely blamed for unprecedented stresses on military couples. Spouses at home must manage families and households without their partner. The strain also has contributed to higher suicide rates and more mental health problems among troops.

"We all agree that there is stress on the families. It's just not manifesting itself in these numbers," a Pentagon spokesman, Lt. Col. Les Melnyk, said about the divorce statistics.

The biggest exception was a rise in divorce rates among military women. For years, their marriages have failed at twice the rate of men in service.

Though firm numbers were not available in the new data, Army divorces in 2007 appeared to occur in about 8 percent of service women's marriages and 2.6 percent of men's.

There is no comparable system for tracking civilian divorces.

The Centers for Disease Control and Prevention said the divorce rate for the general population was 3.6 per 1,000 people in 2005 — the most recent statistics available; that was the lowest rate since 1970.

The per capita divorce rate is different from a second method of calculation — the percentage of marriages that eventually will end in divorce or separation. The CDC said that year that 43 percent of all first marriages end in divorce within 10 years.

Todd Bowers of Iraq and Afghanistan Veterans of America said the wars are having a crushing effect on military marriages and producing a rising number of breakups that are not being tracked because they involve people who have left the service.

"When you look at their numbers ... there's a piece of the puzzle that's missing," Bowers said of the Pentagon statistics.

Army spokesman Paul Boyce said the military divorce rate is not higher because there are "strong programs ... and a sense of real teamwork among the families."

For example:

—The Marines have offered workshops to teach couples to manage conflict, solve problems and communicate better.

—The Navy started a similar program, using weekend retreats for couples.

—The Army has started paying for what it calls its "Family Covenant," a broad initiative of services and facilities to improve the quality of life for military families nationwide and overseas. It includes improving health care, schools, housing and child care to relieve stress on spouses.

—Army chaplains have trained some 60,000 active duty and reservists in the "Strong Bonds" program for strengthening personal relationships.

—Troops also get mental-health training in a program called "Battlemind" that teaches about common problems to expect at home as troops readjust to domestic life.

The Pentagon data does not count actual divorces, but rather takes the numbers of married troops in each service at the beginning of the budget year and the number of married troops at the end. The difference is the estimate of marriages that ended during the year.

Because people come and go during the year — new recruits join, retirees and others leave — those counted at the beginning of the year are not all the same as those counted at the end. This calculation method, however, has remained the same over the years, so officials consider the year-to-year comparison valid.

The numbers also do not speak to troubled but intact marriages. In a mental health survey taken in Iraq in late 2006, 20 percent of troops questioned said they or their spouse were planning a divorce, compared with 15 percent a year earlier.

A study last year showed divorces after several years of war were no higher than in peacetime a decade earlier. It came to the conclusion partly by analyzing personnel records for some 6 million men and women who served in the military the five years before the attacks of Sept. 11, 2001, and the five years after.