An interesting comparison is between scuba diving and hill/mountain climbing.
As has probably been pointed out elsewhere on this forum, a unique study was performed in British Columbia in response to a cluster of deaths. I won't go into details, here is
a link to a summary of the study and on that same page there's link to the full PDF. In summary: the incidence of death was determined to be 2 per 100,000 dives and incidence of DCI 10 per 100,000 dives.
I am from Slovenia, where mountaineering and hill climbing is considered a national sport. They say that if you haven't been to Triglav, the highest mountain at 2864m, you aren't a Slovenian (to which I reply: so what
). Each year quite a few people die in the mountans. I was always interested in comparison between mountaineering and scuba, as far as the safety is concerned and this "article" and video prompted me do do a more thorough search. Eventually I found a
B.Sc. work that describes the work of the mountain rescue service and also includes statistics.
The text is in Slovene - not of much use to you, so here's a resumee. Between 1995 and 2004 inclusive (a 10 year period) there were on average (per year): 232 interventions by the rescue service, 255 people rescued, 126 people injured and 30 deaths.
Of course, the problem, as in scuba, is finding the total number of people in the mountains, but the small size of Slovenia makes this a bit easier. The data in the work suggests that on average there are a 500,000 tourists per year arriving in the towns on or near mountains and an average of 100,000 overnight stays in mountain lodges and cabins. But these two figures don't include the people that come out just for a day. It is estimated that in years with good weather, light winter (so the snow thaws early) there are around 3 million visitors each year.
With this (maximum) estimate, the figures are then (per 100,000 visitors, to make them comparable to the BC study): at least 9 people rescued, at least 4 people injured and at least 1 person dead.
So in all, one can conclude that scuba diving is
at most a factor of 2, not orders of magnitude more dangerous than mountain/hill climbing.
What's interesting, of course, is the difference in perception, since mountaineering is a socially accepted (almost required) activity and a lot of people do it. I can anticipate that during any future debates about the safety of diving, when I whip up these figures, people will start saying: but that's because some mountaineers aren't prepared physically and mentally, they do not know what they're getting into, they disregard safety rules... Which is of course exacly the same in scuba diving!
Of course in both sports there are situations where the odds are just against you and no ammount of preparation can save you. If you ask me, the chances of having a heart attack are much higher in the mountains, where you have to exert yourself.
But the perception is that scuba is dangerous in itself. And it will probably take some time (if ever) before this changes.