ATLANTA — It’s a startling number: 1 in 4 women surveyed by the government say they were violently attacked by their husbands or boyfriends.

Experts in domestic violence don’t find it too surprising, although some aspects of the survey may have led to higher numbers than are sometimes reported.

Even so, a government official who oversaw the research called the results “astounding.”

“It’s the first time we’ve had this kind of estimate” on the prevalence of intimate partner violence, said Linda Degutis of the Centers for Disease Control and Prevention.

The survey, released by the CDC Wednesday, marks the beginning of a new annual project to look at how many women say they’ve been abused.

One expert called the new report’s estimate on rape and attempted rape “extremely high” — with 1 in 5 women saying they were victims. About half of those cases involved intimate partners. No documentation was sought to verify the women’s claims, which were made anonymously.

But advocates say the new rape numbers are plausible.

“It’s a major problem that often is underestimated and overlooked,” said Linda James, director of health for Futures Without Violence, a San Francisco-based organization that advocates against domestic abuse.

The CDC report is based on a randomized telephone survey of about 9,000 women and 7,400 men.

Among the findings:

• As many as 29 million women say they have suffered severe and frightening physical violence from a boyfriend, spouse or other intimate partner. That includes being choked, beaten, stabbed, shot, punched, slammed against something or hurt by hair-pulling.

• That number grows to 36 million if slapping, pushing and shoving are counted.

• Almost half of the women who reported rape or attempted rape said it happened when they were 17 or younger.

• As many as 1 in 3 women have experienced rape, physical violence or stalking by an intimate partner in their lifetimes, compared to about 1 in 10 men.

• Both men and women who had been menaced or attacked in these ways reported more health problems. Female victims, in particular, had significantly higher rates of irritable bowel syndrome, asthma, frequent headaches and difficulty sleeping.

• Certain states seemed to have higher reports of sexual violence than others. Alaska, Oregon and Nevada were among the highest in rapes and attempted rapes of women, and Virginia and Tennessee were among the lowest.

Several of the CDC numbers are higher than those of other sources. For example, the CDC study suggests that 1.3 million women have suffered rape, attempted rape or had sex forced on them in the previous year. That statistic is more than seven times greater than what was reported by a Department of Justice household survey conducted last year.

The CDC rape numbers seem “extremely high,” but there may be several reasons for the differences, including how the surveys were done, who chose to participate and how “rape” and other types of assault were defined or interpreted, said Shannan Catalano, a statistician with the Bureau of Justice Statistics.

“It is an evolving field, and everyone is striving to get a handle on what’s the best estimate,” Catalano said.

The CDC’s numbers don’t seem surprising to people who work with abused women.

“I think that the awareness is growing,” said Kim Frndak, community educator for the Women’s Rescue Center to End Domestic Violence, which operates a shelter on the outskirts of Atlanta.

“More and more people are really saying, ‘Oh, this is something that we need to pay attention to as well,’ because it’s your sister, it’s your mother, it’s your daughter, it’s your son, it’s your brother. Someone in your own circle is being affected by domestic violence, and the effects can be devastating,” she said.

• Online: CDC report: http://www.cdc.gov/violenceprevention/nisvs/