I applied to 22, got invitations to interview at 17, scheduled interviews for 12, went on 11 (got sick at the last one so I skipped it). Most people I met on the interview trail were doing between 8-12, but it definitely felt like the final numbers were tailing off as it got closer to the end. The lowest number I heard of anyone doing was 5, and the highest was over 20 but that person was couples matching with someone going into ortho.
Part of the number to apply to is based on your geographic restrictions or types of programs. Certainly if you're limiting yourself to academic programs west of Denver, that's going to be a very different number of options than if you're willing to apply programs everywhere and include community programs.
