The European Central Bank (ECB) is all about the euro. Established in 1999, ECB and the national central banks of the 16 European Union (EU) member states that use the euro as their primary currency make up the Eurosystem, whose foremost task is to maintain euro price stability. ECB is also responsible for setting the monetary policy of the EU (with the objective of sustained employment and non-inflationary growth), ensuring the smooth operation of payment systems, and managing the foreign reserves of member countries. Its revenue is derived from interest on investments in foreign-reserve assets, money-market instruments, and securities, as well as from the allocation of euro banknotes in the EU.