I count roughly 53 nintendo published titles on the wii (65 if you count wiiware) in north america:
http://en.wikipedia.org/wiki/List_of_products_published_by_NintendoThis is vs (estimated by counting and trying to figure out japan only titles):
NES: 70
SNES: 45
N64: 50
Gamecube: 50
So, with the exception of NES, 50 nintendo published titles seems to be the M.O. A
Also, note: during the NES era, it seems like nintendo published a lot of titles that would normally be 3rd party published today. Probably in an effort to gain steam for the video game industry.