RE: your original question:
I don't know the exact number of unique applicants, but I would sometimes ask the secretaries at interviews how many applications they received and how many interviews they offered per available spot. There were approximately 200-250 applications per program; Baylor even announced by email that they received 244. I was told at Cincinnati that they got nearly 250. Because it's so competitive, people apply to many programs all over the place, so it's likely that the 200+ people who applied to program A on the west coast were the same 200+ people who applied to program B in the Northeast. With ERAS, you just click on the programs to which you want to apply, and while it gets costly it's incredibly simple and quick to submit your application to as many programs as you want.
Hope this helps.