So I have noticed that after owning my MBP for two weeks that no matter how long I leave it plugged in the percentage indicator keeps dropping. On the first day it was at 100. Then over the course of a week it dropped to 99. Now it is at 97. I am now going through the calibration steps that say to run it down until it shuts down, then leave it in that state for 5 or more hours, then charge it until the little light turns green. I have never done this on any rechargeable device I have owned. But I figure that i need to do this since it says 97 instead of 100 percent.