Usually the numbers come from the schools themselves, after polling their students (no one is privy to a student's ROL except the student and the NRMP).
As far as I know, the NRMP does not publically make available stats by school. Some schools will publish them on-line (for example, UTMB in Galveston already has theirs up).
You might check the September Issue of JAMA - every year they devote one to Medical Education. I cannot recall whether it has residency stats or not, but worth a look.
As I'm sure you are aware, knowing this information is potentially helpful. Many students make the mistake of wanting to know WHERE students match - IMHO, it is more important to know whether the students matched at their top choices, whereever that may be and in whatever specialty. I do not expect Podunk U with a primary care mission to field lots of Harvard bound residents. However, I like to hear that a school puts a high percentage of its students in their top 3 choices for residency.
Best of luck finding the info - and please do post it if it surfaces!
