How many balls are used in an average 9 inning game?

Every game starts out with 72 baseballs. The average life of a Baseball, is 6 putches, so if you take the average pitches thrown in a game 250 - 300, you get about 40 or 50 balls used in a game. A side note, every ball that will be used in a game has mud from Mississippi worked into the ball. This is why they are never bright white.