“Swedish Television’s investigating journalists found that in cases where the victims didn’t know the attackers, the proportion of foreign-born sex offenders was more than 80%.”
https://en.m.wikipedia.org/wiki/Rape_in_Sweden
I suspect that excluding cases in which the victims did know the attackers is an effective means of "winnowing out" things like "date rape" - i.e., "morning-after regret" - and "marital rape" - i.e., "How can I level an accusation against my husband in order to upgrade my divorce settlement?"
Regards,