The European Union (EU) is a political and economic union of 28 member states that are located primarily in Europe. It has an area of 4,475,757 km2 (1,728,099 sq mi) and an estimated population of about 513 million. The EU has developed an internal single market through a standardized system of laws that apply in all member states in those matters, and only those matters, where members have agreed to act as one. EU policies aim to ensure the free movement of people, goods, services, and capital within the internal market, enact legislation in justice and home affairs and maintain common policies on trade, agriculture, fisheries, and regional development. For travel within the Schengen Area, passport controls have been abolished. A monetary union was established in 1999 and came into full force in 2002 and is composed of 19 EU member states which use the euro currency.