A total of 19 Member States belong to the European Economic Area (EEA) and adopted the euro (€) in 2002. These make up the "Eurozone", where the euro is the official currency used in all these countries. You have all the information in: «The Schengen area and the Member States of the European Union«.
You have all the information in: "The Schengen area and the Member States of the European Union".