I have played a lot of Morrowind and Skyrim, but have not gone far in Oblivion. In all 3 games there are loads of books strewn about the games. Many of them make multiple appearances, so in a "best guess" type of thing, how many have you (the player) actually read while in game, as opposed to going the http://www.imperial-library.info/?
I'm not sure how many books in all there