measuring book taste by Xanth number

I've had this idea in mind for a while, and was talking to undomielregina about it today.
( Explanation, brief, no really )

So, though I do not have a readership like sdn does and can't get such large amounts of results, I ask you to comment if you can: What is your estimated Xanth number now? And what was it when you actually read them--at least approximately? (I'm guessing that thekinginyellow's is 1, and kat_ravensong's is about 36 or however many have come out--but actually I'm just teasing her. :))

Pleease? Also how much do you like this idea--do you have a better one? (Too bad Dune numbers don't work--there's kind of nothing in between 1 and "all", as far as I know.)