Nearly two-thirds of Americans say sexual harassment is a problem in this country, and about a quarter of women report having been harassed at work, according to a new Washington Post-ABC News poll.

The wide concern may help explain slipping ratings for Republican presidential contender Herman Cain, who is fighting allegations that he made unwanted sexual advances when he ran the National Restaurant Association in the 1990s.

By a ratio of more than 2 to 1, women who say they were harassed at work have unfavorable views of Cain. By an even larger margin — nearly 3 to 1 — they say they are apt to believe Cain’s accusers rather than the businessman.

Cain’s plea that he’s being falsely targeted hits on a fear for many men: In the poll, 25 percent of men say they worry about being unfairly accused of sexually harassing someone. About 10 percent of men said they may have at one time done something, even inadvertently, that a colleague may have considered an unwanted sexual advance. But men today are far less apt than they were in 1994 to say they may have acted inappropriately, even if unintentionally. This decline parallels a slip in concern about workplace harassment since the early 1990s.

Reports of harassment have decreased over time, with fewer women younger than 50 now saying it has happened to them.

Overall, about one in six Americans say they have been sexually harassed at work, including 24 percent of women and 9 percent of men.

The percentage of women saying they have been sexually harassed has fallen from 32 percent in a 1994 ABC News poll, a shift driven almost entirely by younger and more highly educated women.

Seventeen years ago, nearly four in 10 women ages 18 to 49 said they had been sexually harassed at some point. Now, one in four say so. Similarly, 25 percent of college-educated women in the new survey report experiencing harassment, compared with 42 percent in 1994.

There has been a corresponding dip in the number of men younger than 50 expressing concern about being falsely accused and a big drop in the number who think they may have harassed unintentionally. Only 7 percent of men younger than 50 report acting in a potentially inappropriate way, down from 27 percent in 1994.

One number that has tilted in the opposite direction since the 1994 survey is the percentage of people experiencing harassment who say they reported it to their employers.

Still, nearly six in 10 women who said they have been harassed at work said they never reported it. Asked why, 29 percent said they didn’t think it was sufficiently important, 22 percent said they were concerned about the consequences and 19 percent said they didn’t think it would do any good. About three in 10 said it was something else.

Polling director Jon Cohen and polling manager Peyton M. Craighill contributed to this report.