Surprisingly, it's actually a relatively safe sport anymore. (I think there's more injuries and fatalities from bungee jumping) The place I jumped at had been in operation for about 15 years when I went. They had only one injury, and no fatalities up till then. There was a fatality about a year after I went, but the coroner decided the fella had a heart attck on the way down, so never opened his chute.
There's a magazine we used to get for the sport, and in every issue they listed all the accidents around the world from jumping every month, and what the reason was for the accident. Most of the fatalities you hear about are from hot-shots that don't carry a back-up chute, and do the "stunt diving" of one form or another. I think it's just down right stupid not to wear a back-up chute!!