I'm not sure? If all you have to go on is a sample of fanwork from a given author/circle, and that sample consists of mostly gen with some smaller amount of pairing stuff, how would you classify the producer? Is there a significant distinction between "pairing fans who also produce gen" and "gen fans who also produce pairing stuff"? My impression is that fans who produce either pairing stuff exclusively or gen exclusively are uncommon, and that most fall somewhere in between.

12K is neither large (I'd call it middle-sized, but relatively dormant/languishing at the moment) nor typical of anything, in my estimation--I only mentioned it above because it's one of the fandoms I'm most familiar with.