Depends on how you define “Rape”...
If Rape is consensual sex that was done while inebriated at a college party, and someone asking you to go out, then yes, 1 in 5.
If Rape is sex that is forced on another person with physical force..
Then it is a HELL OF A LOT lower than 1 in 5, maybe 1 in 100 or LESS in the western world, don;t worry it will get to 1 in 5 if we keep importing Mudslimes from the middle east, see Cologne Germany for an example.
I have seen a college directive that considered sex as a result of ANY pressure to be "sexual misconduct". A specific example was a threat to break up if she wasn't interested in sex.
As far as inebriated sex, since legal drinking age is 21, one good measure would be to make underaged drinking an expulsion offense. Then, if she says "I was too drunk to give consent", the administration could say "Well, we don't know that. But have just confessed to being intoxicated while underage, so YOU are expelled".
From my viewpoint, the word "rape" should be confined to sexual intercourse where threat of violence was used to impose submission (the classic definition, before modern Political Correctness).