The Canadian dollar posts a weekly loss as data shows a slowing domestic economy.  The Canadian dollar fell against its broadly stronger U.S. counterpart on Friday, registering a weekly decline, as domestic retail sales data added to evidence of an economic slowdown that could spur interest rate cuts.  The loonie was trading 0.6% lower at 1.3605 to the U.S. dollar, or 73.50 U.S. cents, stopping just short of its weakest level in three months which it posted on Tuesday at 1.3613. For the week, the currency was down 0.5%.