Soundwave said:

Pretty sure Wii shipped 25.95 its second (full) fiscal year. That was also the system's peak, it would be all downhill after that, dropping to 20 the next fiscal year, then 15 the following year, and then finally faltering to 9 mill. 

Notable Releases
2006: Wii Sports, Twilight Princess
2007: Wii Play, Cooking Mama, Paper Mario, Mario Party 8, Mario Strikers, Metroid Prime 3, Mario Galaxy, Mario & Sonic, Links Crossbow
2008: Smash Bros., Mario Kart, Wii Fit, Mario Sluggers, Animal Crossing
2009: Wii Sports Resort, Wii Fit Plus, New Mario Bros.
2010: Galaxy 2, DK Returns
2011: Skyward Sword
2012: Mario Party 9

Isn't it funny how sales went downhill when the games stopped coming?

You blame the casuals for the decline of the Wii but the blame is squarely on Nintendo.