The euro is the single currency of the 17 EU member states that form the Euro Area. The euro has replaced the former national currencies, e.g. the Finnish mark, the D-mark and the French franc. The single currency was introduced on 1 January 1999 (2001 in Greece, 2007 in Slovenia, 2008 in Cyprus and Malta, 2009 in Slovakia and in 2011 in Estonia, but existed in the period 1999-2001 only as electronic money. On 1 January 2002 euro banknotes and coins were put into circulation.
The 17 euro area member states have a single currency, a common interest rate and a common central bank.
Denmark has not introduced the euro, but the Danish krone is pegged closely to the euro in ERM II, the EU's exchange rate mechanism.