The federal government attempts to use both monetary policy (control of the money supply through mechanisms such as changes in interest rates) and fiscal policy (taxes and spending) to maintain low inflation, high economic growth, and low unemployment. A relatively independent central bank, known as the Federal Reserve, was formed in 1913 to provide a stable currency and monetary policy. The U.S. dollar has been regarded as one of the most stable currencies in the world and many nations back their own currency with U.S. dollar reserves.