I thought the Ryan report referred to some pretty shocking cases in the 1940s.
I find it hard to believe this stuff comes out of a clear blue sky. Vatican II did not suddenly bring this rot into the seminaries. The seminary directors did not suddenly change their entrance requirements and seek out perverts and pederasts. It would take at least a generation for perverted seminarians to become admissions directors.
Sure, there was a sɛҳuąƖ revolution in the 1960s but for most people that meant sleeping with the opposite sex as adults. I don't see how you would get a sudden spike of child abuse. These things percolate they don't spike.
Not much direct evidence, of course, because it is too long ago. The abusers are dead and the victims very old or dead themselves. But one must also remember that pre Vatican II few victims would have come forward because the stigma attached to accusing a priest of such a thing was enormous. You would have been made a total pariah in your town, the cops would have disbelieved you and the community would have closed ranks on you big time, the media would not have dared to take your side or report the case. Many many people must have feared reporting abuse under those circuмstances.