Your school may have such a resource I know mine does. Also you can post in some of the forums and get an answer. Here are a few I know.
1) EM - right around the national average of 217
2) Ortho- around 230
3) NeuroSurg - 238 Also for many of the early match fields you can get this info from the web site. Just do a google search for either early match or San francisco match.
4) IM - about 220 for a good program
5) OB/GYN I think the average is around 207
6) Neuro around 207