Countries that use the US dollar officially seem to have more dollar coins in circulation. They were common in Ecuador even before the NA and presidential coins were issued. I suspect that they all end up there because they have become used to them. The only way the Fed is going to get them into general use is to withdraw the bills. I would save at least half a billion to switch, a dollop to help with the deficit, but they don't seem to have the will to cut us off from the dollar bill.