The United States is a highly developed country, accounts for approximately a quarter of global GDP, and is the world's largest economy by GDP at market exchange rates. By value, the United States is the world's largest importer and second-largest exporter of goods. Although its population is only 4.2% of the world's total, it holds 29.4% of the total wealth in the world, the largest share held by any country. Making up more than a third of global military spending, it is the foremost military power in the world and a leading political, cultural, and scientific force internationally.BBC, April 2008: Country Profile: United States of America