This is a question I've oft pondered in the wee hours of the night. It's really a one for the ages - Like nature vs. nurture or free will vs. determinism. From the studies I've read (and there are several) it usually varies based on the sample size, and there's some contradictory data as well.
Consider Welsh 2008 who conducted a famous anthropological sample titled, "Celebrities: Society's Unlikely Killers" In it, he used several sampling methods and was supposed to be the final word on this. Of course, we all know in 2011 a review of his work was done, and found that his double-blind studies weren't double-blind at all!
Celebrities are obviously going to have better access to machine guns and various artillery, so that's something to take into consideration right there. Ugh.. It's late and I don't feel like cracking the safe on this one tonight. Let me write down some rough notes and I might come back to this tomorrow.