"Uhh... I'm not sure", 'specially about Canada But probably because we are one of only three nations that still use the English system of measurements instead of the metric. Or should that be the Liberian-Burmese system? No offense, but, proud to be there on the frontiers of science and ground breaking technology with those two forward thinking nations. It's got to do with the enfluence of big bidness on politics in the US. Every time the politicians think about changing, the business lobby hollers about the cost of retooling. ( Our printing presses aren't set up for that.) But now that so many factories are owned by folks in metric nations and most US factories make metric stuff that is out. And of course NASA and the military have gone metric. But then metric is 'foreign', maybe even 'Un-American' and, no doubt,comnist. It promotes humanistic secularism, "If the cubit was good enough for Noah, it's good enough for me." The metric system was invented by them humanists in Revolutionary France. France! That's it. It's just maybe that metrics make too much sense, the math is so much easier ( Divide an inch by half then that half by half and that by half and one 1/128 of an inch? what's that? base 12 feet divided into base 3 yards, how much of a mile is 1/2 inch?) There is no way you can combine a certain number of American bricks to equal a certain thickness of 2X4's and 3/4" plywood. Standard paper makes it real easy to enlarge and reduce image sizes, reduce four pages to fit one one, all kinds of sensible stuff. Now, print a 35mm negative onto 8 by 10 paper .Fold 8 1/2 by 11 in half, 4 1/4 by 11, 5 1/2 by 8 1/2, what kinda ratios is that? But then I am in the graphics trade and it is much more satisfying and romantic to ask for foolscap than a mundane A3, "Double Royals with Elephant inserts for color plates, triple fold Double Portfolios tipped in as end papers!" Dang! I fell like I'm right there with ol Guttenberg hisself.

Canada has gone metric in the early 1970's the USA should have gone along with it, but stuck with the old midevil standard imperial scale, however inspite of the conveniënce of the metric system many Canadians still think and use the old standard while the entire country has switched to metric. Old habits are hard to break, I think the US will convert completely in a couple of years from now, but it will take time for the old standard to be phased out. Americans are known to be stubborn and many of them will not participate in converting to metric, and that,s the main reason why the USA hasn,t gone metric yet.