The single currency was launched in 1999 as an ‘invisible’ currency, which was used only for accounting purposes and electronic payments. It was first introduced in 11 member states: Germany, France, Italy, Belgium, the Netherlands, Luxembourg, Spain, Portugal, Ireland, Austria and Finland. Two years later, Greece joined, too. On 1 January 2002, these 12 EU countries introduced coins and banknotes for the euro. Since then, the eurozone has expanded to include 19 countries: Slovenia (2007), Malta and Cyprus (2008), Slovakia (2009), Estonia (2011), Latvia (2014) and Lithuania (2015).
In principle, the intention is for all EU member states to introduce the euro. However, to do so, they must meet certain requirements, the so-called Maastricht criteria:
- Price stability: The rate of inflation must not exceed a critical value.
- Budget requirements: If a state’s debts are too high, this could put a strain on the euro.
- Exchange-rate stability: Before a country can introduce the euro, it must successfully complete a kind of trial phase, during which its currency is pegged to the euro.
- Similar interest rates: The candidate country’s long-term interest rates must not be too high.
These criteria are all designed to ensure the stable economic development of the countries joining the eurozone and to avoid tensions once the euro is introduced.