A study released Wednesday found that sexual assault and violence against women is much more common in the U.S. than many experts believed.

Nearly one in five women have been reported being sexually assaulted in their lifetimes, and one in four say they've been hit, kicked or experienced violence at the hands of an intimate partner, according to the Center for Disease Control (CDC).

The CDC's National Intimate Partner and Sexual Violence Survey (NISVS) found that "24 people per minute are victims of rape, physical violence, or stalking by an intimate partner."

At 27.2 percent, Oregon was the state with the highest lifetime prevalence of rape. Delaware was the lowest at 14.2 percent.

For sexual violence other than rape, Alaska, at 58 percent, rated the highest. Iowa was the lowest with 33.1 percent prevalence of sexual violence other than rape.

"We were surprised that it was that high," CDC’s National Center for Injury Prevention and Control director Linda Degutis told reporters.

Victim advocates have said for years that rape and sexual violence against women is severely underreported in the U.S.

The Federal Bureau of Investigation’s (FBI) Criminal Justice Advisory Policy Board voted this month to expand the definition of “rape,” after activists bombarded them with thousands of emails insisting that the original, 1929 definition is too narrow.

Activists said the new definition was needed because the current one does not recognize that men can be raped, women can rape women, inanimate objects can be used to commit rape or that rapes can occur while the victim is unconscious.

-- With earlier reporting by Stephen C. Webster