This is how this works.
You start at 90% with 30 games of experience. The chart would show you had 3 quits in games 1, 2 and 3 and finished games 4 through 30 giving you 90%. If you finish 3 straight games, you eliminate the 1, 2 and 3 games and now are at 100%. This is exactly what happened to me, I moved to 100%.
My next 3 games were all blitz, I had 1 player disconnect and lock up the game which counts as a quit for me so now I have 1 through 29 finished and 30 as a quit 97%. Next game same thing, so now I have 1 through 28 finished and 29 and 30 quit 97%. I played a couple of games and finished then another blitz quit. I think that made me 1 - 25 finished 26 27 quit 28 29 finished and 30 quit, back to 90%. Played a couple more game and finished then another disconnect so now I'm at 87%.
You have to remember that to eliminate a quit (be it a real quit or someone else who locked you up) you have to play 30 times to eliminate that one so it stays for a while. It tells me that any percent over 80% is pretty good, esp if you play a lot of blitz.