One of the problems historically in the talley of how many molestations have occured in groups of non-Catholics, is there is no real centralized government, each church hires and fires it’s own minister, they are usually not appointed by a bishop or other authority. They also don’t report abusers to a central authority. So finding the exact number is hard. Here is a link to Dave Armstrong. Former Protestant Minister, and Anti-Catholic now a Catholic apologist.
Poke around his site too.