These statistics aren't even win rate. They're the number of Pokemon knocked out and the number of times they were knocked out. The big difference being that any match that isn't 1 on 1 is usually going to end with every Pokemon being knocked out aside from the last one. The statistics are skewed toward Pokemon who are used last and in 1 on 1 battles.
Let's take Snorlax, for example. Here are his three loses:
>Snorlax has a long battle with Claire's Kingdra, then Gyarados finishes it off because it's tired
>Snorlax beats up Gary's Arcanine and Nidoqueen, then gets finished off by Scizor because it had taken so much damage from the other two
>Snorlax knocks out Harrison's Hypno and Steelix, then gets finished off by Houndoom because it was worn out
Even though nobody's ever managed to defeat Snorlax without throwing multiple Pokemon at it, it still gets marked at 73% because most of its major battles are 6 on 6 (or 2 on 2, in Clair's case). Meanwhile, Ash had a tendency to save Infernape for last, so it was still standing at the end of most of its battles.
