In Major League Baseball (MLB) between 1998 and 2008, an average of 135.6 grand slams were hit per season. Thirty teams play 162 games each (with 2 teams participating in each game), so that means that a grand slam was hit roughly once every 18 games.

Each MBL team was batting about 34 times per game, and a grand slam was hit about once every 1,219 times at bat.

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