Being that I haven't had an interview yet, I have little, if any room to talk. But I would think that would be pretty difficult to answer. Keep in mind the schools are interviewing the top of their applicant pool. However, those top applicants are also the top applicants at other schools. Most of those top applicants will get in somewhere, leaving open spots elsewhere to just the competitive candidates. My opinion would be, if you get an interview before December first, you are in pretty good shape.
However, just getting an interview doesn't guarentee a slot. Someone could have great stats and just unattractive as a potential student (i.e. monotoned, stumbling over words, poorly presented, bad answers to questions, etc.). That person may be thought of as a great investment to one school, but a flat out "no-no" at another. It really seems like some of you kids here with interviews already really don't have anything to worry about. Good luck to all!