Hard to give an average, and it also depends on the player and the caliber of player. Maybe 0.5 to once a match, sometimes a bit more. Banking is usually done as a shot to nothing, a two way shot. There are also some three rail banks some players will shoot, mostly as a safety but sometimes it goes in and if your opponent doesn't know the shot they'll think you flukes something.
The majority of banks in snooker however are into the side pocket and I don't know many snooker players that use spin to make the angle since safety is the primary consideration.
So a snooker player would be able to bank a little bit in one pocket but they wouldn't have the range of options available to them that a pure one pocket player does.
