Ok here it is:
In the United States alcohol in beer is measured by weight (abw), while in Canada it is measured by volume (abv). The two systems produce different figures but for the sake of comparison, a beer that is 5 per cent abv is equal to one that is 4 per cent abw. For example, Coors Extra Gold is 3.9 per cent abw and Labatt Blue is 5 per cent abv. They would have about the same amount of alcohol.
Found that quite interesting. Heres where I found that.
http://www.beer.com/ca/articles/be_a...5_canvsus.html