It's hard to know how many men are rapists, but given that about a 1/3 of women are raped and a smaller, but significant portion of men are raped, 5-10% of men (who are much more common than femal rapists) wouldn't be crazy.

We currently have about 0.7% of the population incarcerated (including kids), most for something besides rape. So incarcerating or executing all rapists would theoretically remove 3-5% of the adult population or 4-7 Million people.

I'm not trying to argue against punishment, I just think it's crazy we have a serious crime that if fully prosecuted would incarcerate, or in your case execute, a mid size state.