In reply to Thom.milburn:
Seems like a strange dissertation title, as many other activities that Outdoor Education students will do are actually more dangerous than rock climbing. Too many people out there label rock climbing as a dangerous sport, when, if it is done sensibly/carefully it isn't. Of course as always with risk it depends how you approach an activity, but many sports such as swimming, biking, running, scuba diving are regularly rated more dangerous than rock climbing e.g. see here:-
http://www.medicine.ox.ac.uk/bandolier/booth/risk/sports.html
Also have a look at Accidents in North American Mountaineering. The 2012 version that I've just read shows a seriously large number of sport climbing accidents, several of them sadly fatal. Also an overwhelming percentage of accidents that are directly a result of human error and were not caused by the natural world.
I agree with Gregor that there is a really big difference between risk of injury and risk of death.... you have to define that difference for your survey to make any sense.
If you include risk of injury then I would rate indoor climbing and bouldering quite high and trad leading quite low. I've done over 1,000 days of outdoor trad leading all round the world, including days cragging, sea-cliffs, long mountain routes and I've never had more than a scratch and only once seen someone else injured. I've been to indoor walls maybe 100-200 times and seen three injuries.
My only mountaineering related accidents have been from summer and winter hill-walking, one accident each, and those activities take up far fewer pages in my log-book.
Anyway I'd go with the following, first figure for death, 2nd for injury
Indoor top roping - 1 5
Bouldering Indoors - 0 5
Outdoor Top roping - 2 5
Bouldering Outside - 1 8
Single Pitch (Sport) - 2 4
Single Pitch (Trad) - 3 6
Multi-Pitching (Sport) 3 5
Multi-Pitching (Trad)- 4 6
Ice Climbing - 6 8
6000m+ Mountaineering - 8 6
Bearing in mind that the vast majority of accidents are caused by human error most of these differences in risk are due to the different environments in which the activities are generally practiced and therefore the more serious consequences of an accident caused by human error. Make a mistake on most multi-pitch trad routes and you will be waiting half a day for medical attention, but make the same mistake on an indoor wall and you could be in hospital in just a few minutes.