I'm currently 15% ahead of schedule, and most of the books I've read this year have been 4500-6000 Kindle locations, so not overly short books either.
I'm doing little else for entertainment lately, I've noticed (doing 10-12 hour work days at the computer so the last thing I want to do once I'm done with work for the day is to spend more time at it and I've basically stopped watching TV or DVDs), so that's certainly the biggest factor.
I've tried to be good about buying books, seeing as I've got a massive to-be-read list (of books I've already acquired), but I've still bought more books than I've read... 74 books bought this year already. Just too many bargains on books in my "that sounds potentially interesting, should grab it when it can be had cheapishly" list, and I keep thinking that I should take advantage of all those Kobo coupons while they a) exist, b) no Agency model applying to me yet to worry about.
So the to-be-read list is still growing at a faster pace. Ah well - not like I'm complaining about having too many books to read and too much choice.