PS3/Wii/360 Tie Ratios ("attach rates") from NPD

[TWRoO]

I can understand Xbox and GC ties [this is USA where XB is popular] but WW i remember GC attaining a record high attach rate of around 9 [so WW XB must be lower]

The 13 for PS2 doesnt seem right at all though.... such a shame this sites data doesnt go back far enough to check.