IF someone is an 'Obvious Cheat' then the only tool available to the Player is the Report feature and perhaps IW's Twitter. I'm not going to 'guess' some erroneous number as a percentage of cheaters especially not on any IW game.
Some players even in Clan Wars are 'slayers' and when you combine a full (Pubstompers) team of 'slayers' then their combined 'KDR' typically goes up. No doubt there are cheaters and not a one AAA title is without them. TAC was pretty effective and IMO considerably better than IAC, and since there is no VAC support in this game there's one less anti-cheat and it's entirely up to IW to ban the players.