What type of punch knocks out opponents the most statistically?

I'd probably put my money on the hook. Straight crosses put a lot of fighters down and on their butt, though not necessarily always KO them. Uppercuts just seem less commonly thrown to see enough KO's from them. I think in most highlight reel KO's, the hook does the most damage and causes the most KOs. You're literally jolting someone's head sideways. The brain is swashing back and forth.