A game that scores should be 50-60% is average (as described by 1up, IGN, EGM, etc.). Think movie games, you don't buy them for the score you buy them for the escapism or role playing (in the traditional sense) of the characters, theme or story. If you really like Transformers or Golf or Dragons a score like this can be acceptable to most (especially the traditional casual player - Generic or Themed Shooters, Mario Party, Madden, etc.) The game lacks precision, features, and presentation but that isn't the most important thing for the people thinking of buying these games in the first place.
Of course scores appear top heavy because there are tons of PC, Cell Phone, and Flash games that aren't reviewed.
I would cite regulation, but I know you will simply ignore it.
