I don't know what source you're referencing, but the USCCB article says that, of the 398 "new allegations," 71% of the alleged incidents of abuse began between the years 1960 and 1984, with the most common time period being between 1975 and 1979.
Just wanted to make the record clear that "398 new allegations in 2009" does not mean that "398 new incidents of abuse were alleged to have occurred in 2009".
It’s becoming more obvious what’s going on: http://www.freerepublic.com/focus/f-news/2481315/posts
I put those statistics up in a couple other threads. I predict there will be no acknowledgment of it by the hyper-Calvinists.