Euro is the official currency of the European Union and used by 19 of the 27 member states. It is the second most traded currency in the world after the US dollar. The euro was introduced on January 1, 1999, as a virtual currency used for electronic transactions and accounting purposes. Three years later, on January 1, 2002, the euro became the official currency of the eurozone, replacing the national currencies of the participating countries. The euro is abbreviated as EUR and symbolized by the € sign.