I did a little digging some time ago. Unfortunately I didn't save sources but I'll give a quick rundown of what I had found.
Various sources state that 1,5% to 5% of the clergy worldwide, between years 1950-1990 has been accused. For the US number is 4%.
Those numbers are roughly consistent with number of pedophilia cases in general population.
The biggest "boom" was in years 1970-1980, years 1950 and 1990 had lowest rate. This trend was also observed in general population.
80% of victims were boys, with 100% of accused werebeing males, obviously.
Those boys were mostly aged between 11 and 17, unfortunately I don't remember what exact portion of all the victims it was. It had been bigger in 1970-1980 then in other years.
Small number of accused priests (something like 5-10%, I dont remember well) were responsible for 30% of cases.
No connection to celibacy, married men and women are as much likely to be pedophiles.
Protestant clergy in US had higher numbers, however iirc the profession that had the highest number were physicians.
No connection to homosexuality, personally I don't believe it but that's what some sources stated so I'm copying it here. They said reason for this is because priests had more contact with boys then girls.
Numbers of pedophilia cases nowadays are very low, iirc correctly for Poland it was 2 priests in last decade. Sceptics say it's because the victims haven't come out yet.
There were also big numbers of sexual abuses in general, not only against kids, but I wasn't looking into numbers.
As for cover-ups I didnt look into much data, but I remember looking into one case where priest was send to psychiatrist for therapy and after it was finished he was assigned to the same parish where he sexualy abused someone again. I remember someone on this board said once that it was believed back then that pedophilia could be cured this way and apparently it turned out to be untrue.
Sources I looked into were often couple years old so keep that in mind.