Honestly they are quite safe. It does happen from time to time though. As a general rule if you look at a operating club over say 30 years if they are unlucky they might have one fatality (more would be rare unless it was a big club). In that time it's likely that they would loose one or more members to car crashes, and of course many to all the normal diseases and smoking etc.
If you don't take off with an engine you don't take one for granted. You are required to fly by the rule that you must always bee within gliding range of a landable field (or paddock). So, at least you don't fly over mulga or densely populated areas like other light aeroplanes.

