NSMBW sells over 500k units in its third week in Japan (1.9M LTD)

[TWRoO]

I don't see the Wii declining in 2010.

I think it will beat 2009, but not match 2008, then decline from then on.

Perhaps:
6 - 18 - 26 - 20 - 23 - 20 - 16 - 13 - 9 - 6 - 2

Though it will depend on what happens at the start of next gen for those last 4-5 years really.