Without some backup, I don't believe the 10 percent number. That is extremely high. That link has no data whatsoever, just a couple quotes. I assume there was mathematical gymnastics used to get to that number.
That said, "Protestant" covers a lot of ground and a whole lot of churches and people in this country so it would not surprise me the number of reports would be higher. I would also say that Protestants don't normally revere the "Church" as infallible or anything like that and might be less likely to let the "Church" take care of it. However, I know I have experience only with a couple denominations.
I suspect differences in polity, and sheer size, make it easier to hide in the RCC. Rome is world wide, many layers deep, and tries to be all things to all Christians. The typical Protestant denomination is a few hundred or thousand congregations, an annual general assembly or synod, and a few institutions it supports, and makes no claim to be itself the one and only true church.
That number does seem high. But, it does happen.
It becomes more problematic when cover ups and perjury come into play.
Mmmmm. Yes.
Church we were at for a long, long time* had a scandal a couple years back. It seems the wife of one of the youth pastors was carrying on with a boy "13 to 16", from the junior high group. Boy's mom got wind (divorced from Dad, and not usually present), did some confronting, and things blew up.
Form the legal side, she (YPW) ended up admitting guilt, doing 60 days in the county jail, and getting 30 months probation. (One wonders, if the genders were other than what they were, if the sentence would have been different.)
Internally, I guess you could say there was not a whole lot of transparency in the way it was dealt with. Word I got from someone in a position to know leads me to think it didn't all come as a complete surprise.
There're too many questions that really can't be answered.
*We're not there now, mostly for other reasons.