Spain is a secular parliamentary democracy and a parliamentary monarchy,[19] with King Felipe VI as head of state. It is a highly developed country[20] and a high income country, with the world’s fourteenth-largest economy by nominal GDP and the sixteenth-largest by PPP. Spain is a member of the United Nations (UN), the European Union (EU), the Eurozone, the Council of Europe (CoE), the Organization of Ibero-American States (OEI), the Union for the Mediterranean, the North Atlantic Treaty Organization (NATO), the Organization for Economic Co-operation and Development (OECD), Organization for Security and Co-operation in Europe (OSCE), the Schengen Area, the World Trade Organization (WTO) and many other international organizations. While not an official member, Spain has a “Permanent Invitation” to the G20 summits, participating in every summit, which makes it a de facto member of the group.