According to the painstaking research by the professionals at MrSkin -
1."Witchcraft": 16 movies, 77 nude scenes.
2. "Friday the 13th": 12 movies, 39 nude scenes.
3. "Hellraiser": 10 movies, 24 nude scenes.
4. "Wrong Turn": 7 movies, 17 nude scenes.
5. "Piranha": 5 movies, 16 nude scenes.
6. "Hostel": 3 movies, 14 nude scenes.
7. "Silent Night, Deadly Night": 6 movies, 14 nude scenes.
8. "Halloween": 13 movies, 13 nude scenes.
9. "Amityville": 23 movies, 9 nude scenes.
10. "Nightmare on Elm Street": 9 movies, 8 nude scenes.