WINNIPEG – The Canadian dollar sank to its lowest closing exchange rate since last October on Friday. The loonie closed at US$0.7217 or US$1=C$1.3857, compared to US$0.7233 or US$1=C$1.3825 on Thursday. The United States Dollar Index was down 0.05 of a point at 106.55. Crude oil prices surged on Friday after the U.S. conducted air