Depends on at which schools you're interviewing. Statistically, many schools accept half the people they interview. But don't feel like you'll squeek in because your "chances" are good. I didn't feel confident about an acceptance until I actually got the phone call. Theoretically, you could get an interview at every U.S. school and still get no acceptance; there's a lot of anecdotal evidence around here about people who got 10 interviews and 10 waitlists, eventually no acceptances.
Many interviews =/= acceptance
However, in my mind, I was feeling pretty good once I had 5 interviews at schools where I felt like I was a strong competitor.
It depends on your personality (how paranoid, anxious, confident, arrogant, level-headed, insecure, etc you are), your qualifications, where you applied, how you interview...