Would my generalization that 60% of women in society commit forbidden acts be considered slandering chaste, unsuspecting women, and do I have a way to repent if that is the case?

It is impermissible to generalize insults or slanders to an entire community or a portion thereof, due to the prohibition against lampooning an entire tribe, and because such an act involves injustice, the spreading of sin, and looking upon people with disdain. Your statement, "The women of this society associate with men and have relationships that are not fornication, and they watch what Allah has forbidden," is not slander (qadhf). Slander is the accusation of fornication or sodomy. As long as you have not explicitly accused the women of fornication, then this is not a slander that necessitates the prescribed punishment (hadd). However, it is a statement that requires repentance, guarding one's tongue, and caution against uttering such words concerning people's honor.