Mexico City, officially City of Mexico, is the capital and most populous city of the United Mexican States. As an "alpha" global city, Mexico City is one of the most important financial centers in the Americas. It is located in the Valley of Mexico (Valle de México), a large valley in the high plateaus at the center of Mexico, at an altitude of 2240m. The city consists of sixteen municipalities (previously called boroughs).The 2009 estimated population for the city proper was approximately 8.84 million people, with a land area of 1485km2. According to the most recent definition agreed upon by the federal and state governments, the Greater Mexico City population is 21.2 million people, making it the largest metropolitan area of the world's western hemisphere and both the tenth-largest agglomeration and largest Spanish-speaking city in the world.The Greater Mexico City has a gross domestic product (GDP) of US$411 billion in 2011, making Mexico City urban agglomeration one of the economically largest metropolitan areas in the world. The city was responsible for generating 15.8% of Mexico's Gross Domestic Product and the metropolitan area accounted for about 22% of total national GDP. As a stand-alone country, in 2013, Mexico City would be the fifth-largest economy in Latin America—five times as large as Costa Rica's and about the same size as Peru's.