The OC Register has an online feature where you can search a database of Orange County theme park injuries reported in 2009 and 2010.
I found it amazing that only 284 injuries were reported over two years for all of Orange County theme parks combined (DL, DCA, Knott's, Soak City, etc.). In other words, across all the parks in Orange County there was less than one injury reported every two days.
At Disneyland the most reports (14) were for Splash Mountain, but none of the injuries was due to a problem with the ride and no changes to the ride were required to be made. I went through several of the attractions in the database and the majority of reports I saw were of injuries endured while people were getting on and off rides rather than things happening on the rides. One on-ride "injury" was a woman reporting she was bitten by a mosquito on Pirates of the Caribbean!
Anyway, it's a useful and interesting thing to spend some time searching through.
Here's the link.