Am I the only one horribly confused by the math in these charts?

E.G. the second chart has FF at 20.08% and then has a breakout where they show FF15 at ~11%, FF14 at ~3.2%, FF13 at ~0.7%, and FF12 at ~1% Those add up to ~16% by my math... That leaves around 4% missing, I'm assuming in an "other" category, but I feel like leaving off "other" when it's your second largest grouping is bad presentation.

Anyone else have a less confused way of reading these graphs?