El Salvador /ɛl ˈsælvədɔr/, officially the Republic of El Salvador, is the smallest and the most densely populated country in Central America. The country's capital city and largest city is San Salvador. Important cultural and commercial centers for Central America on the whole include Santa Ana and San Miguel. El Salvador borders the Pacific Ocean on the south, and the countries of Guatemala to the west and Honduras to the north and east. Its easternmost region lies on the coast of the Gulf of Fonseca, opposite Nicaragua. As of 2009, El Salvador had a population of approximately 5,744,113 people, composed predominantly of Mestizos.The colón was the official currency of El Salvador from 1892 to 2001, when it adopted the U.S. Dollar.In 2010 El Salvador ranked twelfth among Latin American countries in terms of the Human Development Index and fourth in Central America, due in part to ongoing rapid industrialization.The indigo plant, which yielded a rich blue dye, was El Salvador's most important crop during the colonial period; its place was taken by coffee in the second half of the 19th century. Between 1871 and 1927 coffee production so dominated the country's economy that it was known as the Coffee Republic, and by the early 20th century, coffee accounted for 90 percent of the country's export earnings. Its importance to the economy began to decline after the Great Depression; by 1987 it was responsible for half of export earnings, and by 2004 coffee production accounted for only 7 percent.