You are looking at a chart. Congratulations. It shows the GameRankings for Xbox 360, PS3 and the Nintendo Wii. Looking at all the games released for those consoles, the GameRankings for them seem to have the biggest difference for the Wii. Out of the 189 Wii games released, 37 per cent have been ranked "poor" with an average ranking of 60 per cent or lower, while 11 per cent are "good" with an average ranking of 80 percent or higher. That 11 per cent is 20 games — four of which are PS2/GameCubes ports. Those 16 games, though, are pretty dang great. The rest is... Nintendo Seal of Quality anyone?
Wii Exposed [GameFunk via Go Nintendo]