Become a MacRumors Supporter for $50/year with no ads, ability to filter front page stories, and private forums.
I have only had it off for a couple of days. At this point in the day, with as much usage as I've had, I'd expect to be around 50%. I'm actually at 66%. I really need to give it a few more days to be sure though.
 
Register on MacRumors! This sidebar will go away, and you'll see fewer ads.