The curves fluctuate slightly each year, but they are similar from year to year. Using appass.com, I got the following.
AP Spanish Language: 116/150 or 77.3%
AP Computer Science: 61/80 or 76.25%
AP English Language: 109/150 or 72.7%
AP Chemistry: 68/100 or 68%
AP US History: 110/180 or 61.1%
All of them should be pretty accurate, although I know that APUSH had a change in the exam last year, and the data from appass is from 2006.