Executive branch: Chief of state: President Barack H. OBAMA (since 20 January 2009); Vice President Joseph R. BIDEN (since 20 January 2009); note - the president is both the chief of state and head of government head of government: President Barack H. OBAMA (since 20 January 2009); Vice President Joseph BIDEN (since 20 January 2009) cabinet: Cabinet appointed by the president with Senate approval elections: president and vice president elected on the same ticket by a college of representatives who are elected directly from each state; president and vice president serve four-year terms (eligible for a second term); election last held 4 November 2008 (next to be held on 6 November 2012) election results: Barack H. OBAMA elected president; percent of popular vote - Barack H. OBAMA 52.4%, John MCCAIN 46.3%, other 1.3%. Capital: Washington, DC Population: 307,212,123 (July 2009 est.) 295,734,134 (July 2007 est.) Languages: English 82.1%, Spanish 10.7%, other Indo-European 3.8%, Asian and Pacific island 2.7%, other 0.7% (2000 census) Location: North America, bordering both the North Atlantic Ocean and the North Pacific Ocean, between Canada and Mexico Climate: mostly temperate, but tropical in Hawaii and Florida, arctic in Alaska, semiarid in the great plains west of the Mississippi River, and arid in the Great Basin of the southwest; low winter temperatures in the northwest are ameliorated occasionally in January and February by warm chinook winds from the eastern slopes of the Rocky Mountains Land boundaries: total: 12,034 km border countries: Canada 8,893 km (including 2,477 km with Alaska), Mexico 3,141 km note: US Naval Base at Guantanamo Bay, Cuba is leased by the US and is part of Cuba; the base boundary is 28 km Background: Britain's American colonies broke with the mother country in 1776 and were recognized as the new nation of the United States of America following the Treaty of Paris in 1783. During the 19th and 20th centuries, 37 new states were added to the original 13 as the nation expanded across the North American continent and acquired a number of overseas possessions. The two most traumatic experiences in the nation's history were the Civil War (1861-65) and the Great Depression of the 1930s. Buoyed by victories in World Wars I and II and the end of the Cold War in 1991, the US remains the world's most powerful nation state. The economy is marked by steady growth, low unemployment and inflation, and rapid advances in technology. Administrative divisions: 50 states and 1 district*; Alabama, Alaska, Arizona, Arkansas, California, Colorado, Connecticut, Delaware, District of Columbia*, Florida, Georgia, Hawaii, Idaho, Illinois, Indiana, Iowa, Kansas, Kentucky, Louisiana, Maine, Maryland, Massachusetts, Michigan, Minnesota, Mississippi, Missouri, Montana, Nebraska, Nevada, New Hampshire, New Jersey, New Mexico, New York, North Carolina, North Dakota, Ohio, Oklahoma, Oregon, Pennsylvania, Rhode Island, South Carolina, South Dakota, Tennessee, Texas, Utah, Vermont, Virginia, Washington, West Virginia, Wisconsin, Wyoming International organization participation: ADB (nonregional member), AfDB (nonregional member), ANZUS, APEC, Arctic Council, ARF, ASEAN (dialogue partner), Australia Group, BIS, BSEC (observer), CBSS (observer), CE (observer), CERN (observer), CICA (observer), CP, EAPC, EBRD, FAO, G-20, G-5, G-7, G-8, G-10, IADB, IAEA, IBRD, ICAO, ICC, ICCt (signatory), ICRM, IDA, IEA, IFAD, IFC, IFRCS, IHO, ILO, IMF, IMO, IMSO, Interpol, IOC, IOM, ISO, ITSO, ITU, ITUC, MIGA, MINUSTAH, NAFTA, NATO, NEA, NSG, OAS, OECD, OPCW, OSCE, Paris Club, PCA, PIF (partner), SAARC (observer), SECI (observer), SPC, UN, UN Security Council, UNCTAD, UNESCO, UNHCR, UNITAR, UNMIL, UNRWA, UNTSO, UPU, WCL, WCO, WFTU, WHO, WIPO, WMO, WTO, ZC GDP (purchasing power parity): $14.26 trillion (2009 est.) $12.37 trillion (2007 est.) GDP - per capita: PPP $46,400 (2009 est.) purchasing power parity - $41,800 (2007 est.) GDP - composition by sector: agriculture: 1.2% industry: 21.9% services: 76.9% (2009 est.) agriculture: 1% industry: 20.7% services: 78.3% (2007 est.) Agriculture - products: wheat, corn, other grains, fruits, vegetables, cotton; beef, pork, poultry, dairy products; forest products; fish wheat, corn, other grains, fruits, vegetables, cotton; beef, pork, poultry, dairy products; forest products; fish Industries: leading industrial power in the world, highly diversified and technologically advanced; petroleum, steel, motor vehicles, aerospace, telecommunications, chemicals, electronics, food processing, consumer goods, lumber, mining. National Resources: coal, copper, lead, molybdenum, phosphates, uranium, bauxite, gold, iron, mercury, nickel, potash, silver, tungsten, zinc, petroleum, natural gas, timber note: the US has the world's largest coal reserves with 491 billion short tons accounting for 27% of the world's total Environment - current issues: air pollution resulting in acid rain in both the US and Canada; the US is the largest single emitter of carbon dioxide from the burning of fossil fuels; water pollution from runoff of pesticides and fertilizers; limited natural fresh water resources in much of the western part of the country require careful management; desertification Environment - international agreements: party to: Air Pollution, Air Pollution-Nitrogen Oxides, Antarctic-Environmental Protocol, Antarctic-Marine Living Resources, Antarctic Seals, Antarctic Treaty, Climate Change, Desertification, Endangered Species, Environmental Modification, Marine Dumping, Marine Life Conservation, Ozone Layer Protection, Ship Pollution, Tropical Timber 83, Tropical Timber 94, Wetlands, Whaling signed, but not ratified: Air Pollution-Persistent Organic Pollutants, Air Pollution-Volatile Organic Compounds, Biodiversity, Climate Change-Kyoto Protocol, Hazardous Wastes