Only one of the cast members of Jersey Shore was actually from NJ, despite the fact that the program was filmed here and had our name. The rest were mostly from "the islands" (i.e., Long, Staten, and Rhode).
As for the low rate of STDs, it is significantly lower than the rest, which is rather remarkable, especially if the figures do represent counties or cities and not just campuses. Perhaps this also fits into the argument often used when discussing our fan base and illustrates that people really do have a lot more to do entertainment-wise than most of our B1G brethren. I recall being very surprised at the high level of promiscuity at OSU when I was there, compared to what I saw at Rutgers, but that may comparing apples to oranges since the only women around back then were over at Douglass, since Rutgers College was still an all-male bastion.
To me, the most surprising figures were the high scores for Northwestern (which lends credence to the argument that the figures are for Cook County and not just for the campus) and UMd, where there really are a lot more things to do in the area than for most of the Midwestern members.