The United Mexican States (Spanish: Estados Unidos Mexicanos), or commonly Mexico (IPA: /ˈmɛksɪkoʊ/) (Spanish: México IPA: [ˈmexiko]), is a federated Union of thirty-one states and a federal district located in North America. It is bounded on the north by the United States; on the south and west by the North Pacific Ocean; on the southeast by Guatemala, Belize, and the Caribbean Sea; and on the east by the Gulf of Mexico.The United Mexican States comprise a constitutional republican federation of thirty-one states and a federal district, the capital Mexico City, which is one of the most populous cities on Earth. Covering almost 2 million square kilometers, Mexico is the fifth-largest country in the Americas by total area and the 15th largest in the world. As a regional power and the only Latin American member of the Organization for Economic Co-operation and Development (OECD) since 1994, Mexico is firmly established as an upper middle-income country. Mexico is the 12th largest economy in the world by Gross Domestic Product (GDP), on par with countries like Canada and Spain, even though income inequality is still high. The economy is strongly linked to those of its North American Free Trade Agreement partners. Elections held in July 2000 marked the first time that an opposition party won the presidency from the Institutional Revolutionary Party (Partido Revolucionario Institucional: PRI) which had held it since 1929, culminating a process of political alternation that actively had begun at the local level during the 1980s.