He is saying Class not specifically combo priest.
Off Most Popular Quest Shaman Data:
Off this deck broken down for recorded priest games:
Combo Priest 2,900 games 35 percent OF PRIEST opponents
Resurrect Priest 3,600 games 43.9 percent OF PRIEST opponents
There are two other lesser known archetypes of Quest Priest.
Add them all together and you get 100 percent. Add all the games together and that is the recorded games with priest as the opponent FOR THAT SPECIFIC DECK.