The Duke sociologist Kieran Healy looked at four journals--Philosophical Review, Journal of Philosophy, Nous and Mind--for the indicated period; this started making the rounds last week, but now Professor Healy has finished various corrections and revisions.
The original Co-Citation Network post:
The dynamic visualization accompanying the post:
A static snapshot of the network:
Citations to David Lewis and to women, with information on gender patterns in citations:
And here are "poster" versions, with the pictures and information on both the overall graph and the gender stuff, both a (large) PNG file suitable for linking or embedding on a webpage:
and a PDF of the same thing, suitable for printing into an actual poster,
It would be interesting to see how the results, especially for gender, would be affected by adding Ethics or Journal of the History of Philosophy or Oxford Studies in Ancient Philosophy to the mix.