My IM PD told me a few months ago that the number of applicants to IM has been decreasing every year, particularly the number of US grads. I haven't heard anything specific about this year's numbers, but with the new 80 hr work week, I suspect that this year will continue the trend with even fewer applicants in IM since people will be more willing to consider the surgical subspecialties if that's what they really want to do with the more humane training hours. ~85% of US med students get into one of their top three choices in residency programs, I suspect that the percentage for IM matching into the top 5 is pretty close to 95-100% for US grads. When I say top 5 though, I am referring to the top 5 programs who invited you for an interview. If you are talking about top 5 programs in the nation that you happen to like, that's still going to depend on your strengths as an applicant, your letters, and your numbers. The top 5 IM programs (Harvard, Hopkins, etc) mainly interview AOA applicants or applicants with things on their CV that make them "unique".