Wii has moved under 200,000 a few weeks this year, but rebounded with stronger than normal weeks after. Generally speaking it seems that months with few Nintendo releases coincide with low Wii sales.
January had Warioware/Fire Emblem/Wii Play (USA/Jap/Others)
February had Wii Play (US)
March had .... (nothing? I need to check on this)
April had Super Paper Mario (USA/Japan)
May had Mario Party 8 (USA) Strikers (Europe...I think that is when it came out)
June had Big Brain Academy/Pokemon Battle Revolution (USA)
July had Mario Strikers (USA), Mario Party 8 (Japan I think)
August had Metroid Prime 3 (USA)
September has Super Paper Mario (Eur)/Strikers (Japan)
October has Batallion Wars (USA)
November has Galaxy (USA/Japan/Others) and maybe Brawl for Japan, and Prime 3 for Others
December has Brawl (USA), Wii Fit (Japan)
Obviously September should be down a bit until Strikers releases in Japan, and once the Metroid boost wears down a bit I imagine Wii will be back in the 85k range in the Americas until October.