The same system as the U.S., known as the Imperial or Customary System.

1) "All countries across the globe have officially adopted the metric system except the United States of America, Liberia and Burma (Myanmar). These remaining countries have not officially adopted metric but have done so to some degree indirectly through international trade and standardisation. Liberia and Myanmar are both substantially metric countries that trade internationally in metric units. Visitors to these places report that they also use metric units for most things internally with only a few exceptions like old (ancient) petrol pumps calibrated in British Imperial gallons." Source and further information: http://en.wikipedia.org/wiki/Metrication 2) "What countries besides the U.S. have not adopted the metric system? Many U.S. teachers think the answer is "Liberia and Burma" (make that Myanmar). Let's give Liberia and Myanmar a break! All countries have adopted the metric system, including the U.S., and most countries (but not the U.S.) have taken steps to eliminate most uses of traditional measurements. However, in nearly all countries people still use traditional units sometimes, at least in colloquial expressions. Becoming metric is not a one-time event that has either happened or not. It is a process that happens over time. Every country is somewhere in this process of going metric, some much further along than others." Source and further information: http://www.unc.edu/~rowlett/units/ 3) "There is an old folk song that contains one of the quintessential travel lines: "You can hear the whistle blow a hundred miles." But if you live outside of the three countries that still utilize the Imperial units of measurement(including the United States, Myanmar and Liberia), then the metric system is the measurement standard that is used, and the song does not make as much sense. That is, unless you know mileage conversion from the Imperial mile to the metric kilometer. " Source and further information: https://www.amazines.com/article_detail.cfm?articleid=606608