http://www.nationalsexstudy.indiana.edu/
rather interesting results for a topic that most dont do in-depth research.
from the main page...
On this site, we make available this special issue of The Journal of Sexual Medicine, with the goal of helping to facilitate the use of this data to inform the development of public health programs designed to improve the sexual health of our society.
“This survey is one of the most expansive nationally representative studies of sexual behavior and condom use ever conducted, given the 80-year span of ages,” said Michael Reece, director of the Center for Sexual Health Promotion. “These data about sexual behaviors and condom use in contemporary America are critically needed by medical and public health professionals who are on the front lines addressing issues such as HIV, sexually transmissible infections, and unintended pregnancy.”