McCarthy is a very good player, don't for a second think I feel otherwise, but those stats only tell a part of the story..
You have 11 players, the manager and the opposition that all go towards deciding whether you keep a clean sheet or win a game, McCarthy may help more than his replacement but is not responsible for the wins or clean sheets alone. Others will quote Howard being out as the reason we do well, or the manager changing tactics, or getting breaks from the ref, good fortune, poor opposition etc... using team stats to prove one players ability doesn't quite work imo.
He is quality and I think he should be played, but I don't think he is world class, or even as good as most of those quoted.
He's defo worth more than 13m now though. Good purchase from Martinez