Russia is a great power, and a potential superpower. It is ranked as "very high" in the Human Development Index, with a universal healthcare system, and a free university education. Russia's economy is the world's eleventh-largest by nominal GDP and the sixth-largest by PPP. It is a recognized nuclear-weapons state, possessing the world's largest stockpile of nuclear weapons; with the second-most powerful military, and the fourth-highest military expenditure. Russia's extensive mineral and energy resources are the world's largest, and it is among the leading producers of oil and natural gas globally. It is a permanent member of the United Nations Security Council, a member of the G20, the SCO, the Council of Europe, the APEC, the OSCE, the IIB and the WTO, as well as the leading member of the CIS, the CSTO, and the EAEU. Russia is also home to the ninth-greatest number of UNESCO World Heritage Sites.