Twenty percent of young women who attended college in the United States during the past four years say they were sexually abused, a recent Washington Post-Kaiser Family Foundation poll showed.

Surprisingly, however, the respondents say sexual assault is not their primary problem in school.

The actual number of victims in American campuses may even be greater, according to a recent Washington Post report based from one of the most up-to-date and extensive surveys taken on the subject. The survey covered more than 1,000 people nationwide who have attended college from 2011 to 2015, asking them about sexual assault and campus culture.

Some of the survey respondents said they were forced to have sex after receiving verbal threats or promises while others say they were violated without their consent. Others even recounted how they went through the attempted attacks.

The poll revealed that 25 percent of young women and 7 percent of young men were victims of unwanted sex while in college from 2011 to 2015.

Two-thirds of the victims say they were under the influence of alcohol before the incidents occurred.

The poll provides evidence that sexual assault is often linked to factors considered as part of campus culture. One of these factors is alcohol consumption. Two-thirds of the victims say they had been drinking alcohol just before they were sexually abused.

The poll cites two other potential risk factors—casual romantic encounters known as "hookups" and the presence on campus of fraternities and sororities.

The findings highlight the difficulty college administrators face in trying to prevent violence which has been described as widespread but rarely reported to authorities.

Sex abuse cases that land on the dean's desk or in the courts more often raise the difficult question: Did the accuser and the alleged assailant agree to have sex?

The poll says the respondents themselves have mixed views on sexual consent. Forty-six percent said they are unsure whether sexual activity when both people have not given clear agreement is sexual assault. Forty-seven percent called that scenario sexual assault.

The poll notes that the respondents did not put sexual assault as their main concern in school. Thirty-seven percent described it as a just another problem on campus. Fifty-six percent viewed alcohol and drug use as a more serious problem than sexual assault.

The students generally expressed confidence in how their schools deal with sex abuse reports. More than two-thirds gave their colleges an A or a B for their handling of complaints. Only 8 percent gave their schools a D or an F.