Ummmm... I'll try to be accurate, even though I don't remember exactly
Twilight: 7 times
New moon: 3 times the whole book, MUCH more than that chapters 1-3 & 17-24 + the preface and the epilogue of course
Eclipse: Oh God, that's my favorite... I really don't remember... more than 15 times, for sure
Breaking Dawn: 5 times,well until now (it only came out in Greece this summer, but I read it in English anyway, it only takes me a little more time, and it's always better to read a book in its original language)
(So, please excuse my english, it's not my native language and I'm trying really hard to get better!