I visit my girlfriend in CT fairly often, crossing the border to that state always freaks me out when people don't have helmets on. I'll never forget being behind a guy on his sportbike with a girl on the bike. We come up to a stoplight, he puts his foot down, slips they both go down. Both heads hit the pavement. I could HEAR their heads hit with my windows up from behind them. Lots of blood, one of them twitching the other not making any other movement. They weren't even MOVING and neither one lived. That sound will forever be in my memory, not to mention the image. I've always worn a full face, and always will. Not just because of that, but that whole thing still makes me shudder.
I've been down a few times and if I wasn't wearing a full face I wouldn't have a face right now...so all in all, not wearing a helmet is not an option for me.
Dusterdude: Good point, but I don't think the number of riders increased THAT much over that period of time. I'm sure there was a surge, but I can't imagine that much.