Thanks for your comments. It happens that I worked in the safety field and often worked with statistics, accident rates, and compared clients with statistics collected by the National Safety Council (NSC)and the Bureau of Labor Statistics OCWC/OSH. The problem with recreational activities (climbing, scuba diving, river rafting and such) is the collection of data. First you get a lot of anecdotal data from people who are not trained in accident invistigation, so you don't really know the true (proximate) cause of the accident. Secondly, we don't have good records of the hours of exposure,or even the number of people doing it, so the rate is not possible to accurately calculate. But enough of this. Sorry I rambled on so. I used to find this all very interesting.