Which countries of the world have not formally begun converting to the metric system?

In 1960, the metric system was officially named the Système International d’Unités (or SI) and is now used in nearly every country in the world except the United States, Burma (also known as Myanmar, in Southeast Asia), and Liberia. As early as 1790, Thomas Jefferson, then the U.S. secretary of state, proposed adoption of the metric system. It was not implemented because Great Britain, America’s major trading source had not yet begun to use the system.