Depends on the interval in question. Over a large enough sample it's all skill. over ONE instance though...
-over one PFAI hand it's something like 75% luck.
-Over one average cash hand it can be anywhere between 30 and 60% luck, depending on how thinly you play and your skill gap to your villains (a solid, nitty 19/17 TAG at a table full of fish might rely as little as 20% per hand on luck).
-over one STT it's probably 50-60%-ish luck.
-over one MTT it's seriously something like 90% luck or more, which is why I hate MTTs. You just cannot avoid being all-in preflop a dozen times over the course of a tourney, and the odds
of winning ALL those flips (or even just enough to stay alive) are massively stacked against you.