Yeah, I noticed this too, but I wonder if it's an apples-to-apples comparison. Wii had an awful lot of downloadable games, and I wouldn't be surprised if those counted towards its tie ratio. Do you know?
I don't know, but either way (disc-based, download-only, or both), it means people are buying and playing a good amount of games on the Wii...which contradicts those who say most people only bought a Wii to play Wii Sports and nothing else.