The rules for joining the euro
1) Countries must have a budget deficit of less than 3% GDP;
2) Countries must have government debt of less than 60% their GDP, or be on a declining trend;
3) Countries must have inflation within 1.5% the average figure for the three countries with the lowest inflation in the EU;
4) Domestic bond spreads must not be more than 2% over German bunds;
5) Countries must be a member of the ERM2 system, without causing severe tensions, for at least two years prior to Euro membership.