Interesting stuff. James Burns has basically made a career out of AfD, so I'm not surprised to see he is the top contributor in this sample. I think his contributions and Etacar's and mine are probably distorted somewhat by selective voting. For instance I won't bother voting at all on most nominations because they're going to be deleted anyhow and I agree with the deletion. The few that I do look at and vote delete on are generally cases where I think it look marginal and I investigate. Probably most of the 500+ keeps I made were related to topics of interest to me. Programming languages, schools, roads. Stuff that I think should be in the Library of Babel.
Also I have the worst judgement for nomination of anyone I know. If I nominate an article for deletion, it will probably end up as a FAC within a month.