The following table contains approximate figures for gross domestic product (GDP) and the national debt in the United States for June 2005 and June 2011. The national debt represents the total amount of money owed by the federal government to holders of U.S. securities. All numbers are in trillions of dollars. June 2005 June 2011 GDP (Trillions of Dollars) 12.3 15.2 Total National Debt (Trillions of Dollars) 7,8 14.3 Source: "U.S. Treasury, Bureau of Economic Analysis." Debt Held by Federal Government and Federal Reserve (Trillions of Dollars) 4.0 4.6 Debt Held Outside Fed. Govt. and Fed. Reserve Foreign Ownership U.S. Ownership (External National Debt) (External National Debt) (Trillions of Dollars) (Trillions of Dollars) 1.9 4.5 1.9 5.2 Net public debt is the portion of the national debt that is held outside the federal government and the Federal Reserve System. In June 2005, the net public debt as a percentage of total national debt was In June 2005, the percentage of the U.S. national debt held by foreigners (external national debt) was The fraction of the national debt held by foreigners will eventually need to be repaid to foreigners, thereby reducing the collective purchasing power of Americans. Between 2005 and 2011, the fraction of the national debt held by foreigners The absolute level of the debt does not necessarily provide a clear indication of a nation's debt burden. Thus, economists often look at relative measures of the national debt. One possible relative measure of the national debt is the federal debt held by the public (outside the federal government and the Federal Reserve) as a percentage of GDP. In 2005, publicly held debt was of GDP. Between 2005 and 2011, publicly held debt as a percentage of GDP