Canadian average largely depends on location. Many northern states get many, but here in southern california they are not too common.
My averages are:
7.7 wheats per box of cents.
1 Indian Head cent
per 43 boxes of cents.
2.77 canadians per box of cents.
1 buffalo every 3.38 boxes of nickels.
1 canadian per every 1.41 boxes of nickels.
Haven't done boxes of halves, I just get silver sometimes from teller trays. And I've never seen a canadian half?