I believe the the original 1 in 6 statistic comes from a national survey conducted in 1996 (not by the Colorado Coalition against Sexual Violence, pace ESR), in which 17.6 % of the surveyed women said they had been victims of completed or attempted rape in their lifetimes. In the survey questions, rape was explicitly defined as vaginal, oral or anal penetration under force or the threat of force.
I believe the the original 1 in 6 statistic comes from a national survey conducted in 1996 (not by the Colorado Coalition against Sexual Violence, pace ESR), in which 17.6 % of the surveyed women said they had been victims of completed or attempted rape in their lifetimes. In the survey questions, rape was explicitly defined as vaginal, oral or anal penetration under force or the threat of force.