Actually, a lot of you will probably be surprised to learn that the 'official' measuring system in the U.S. is indeed metric. (freedom distances - that's funny!). Our government declared it official several years ago (unless they undid it). However, the problem is that all of our tooling, machines, and manufacturing equipment in all industries (including the expensive computer numeric control stuff) doesn't yet do metric. Very slowly we are drifting that way and where I work we put both dimensions on most technical drawings - but we do a lot of work overseas that's driving most of our changes.