About 30% of students don't drink at college.
I teach at a college and I often show my students some of the ACHA stats to let them know about the wide range of normal and typical behavior at college - you can act or not act in many ways and many others are doing the same.
ACHA Results are here:
http://www.acha-ncha.org/reports_ACHA-NCHAII.html
If you look at the undergraduate reference group - alcohol related questions start on page 18 I think. The questions before that ask what they think a typical students does. Those are also interesting because their perceptions of what others do is very 'off' compared to what students actually report.