Nations using foreign currency
Countries without their own money using the U.S. dollar include: Ecuador, Micronesia, Palau, Turks & Caicos, East Timor, El Salvador, Marshall Islands, British Virgin Islands and Zimbabwe. The dollar is the most widely used currency in the world, Panama has had the U.S. dollar as legal tender since 1904, with the Panama balboa, and is seen as a special situation for the canal.
Source: Numiscadero Spanish to English Glossary (Gary Beals)