BRUSSELS (Reuters) – The European Commission said on Wednesday that none of the six European Union countries that do not yet exploit the euro meet the criteria for euro zone membership, although Bulgaria was the closest.

Of the 27 countries that make up the EU, Sweden, Poland, the Czech Republic, Bulgaria, Romania and Hungary still exploit their own currencies rather than the euro, but are legally obliged to eventually adopt the single currency.

Denmark also continues to exploit its own currency, but is legally exempt from adopting the euro.

“None of these Member States currently meet all the criteria for joining the euro area. Bulgaria is the only country that meets all but one of the criteria and where national legislation can be considered compatible with the principles of Economic and Monetary Union.” said the Commission.

To start using the euro, each of the six countries must meet the criteria of low inflation and borrowing costs, public debt and deficit in line with EU law and a stable exchange rate.

They must also ensure that their central bank law is consistent with EU law on the European Central Bank in order to protect the independence of the central bank, prohibit central bank financing and integrate the national central bank into the European System of Central Banks.