As the highlighted areas show, cumulative debt as a percent of Gross Domestic Product decreased steadily after World War II highs of 90%. It increased during the Reagan-Bush Administrations and under the current Bush Administration. In September 2008, it hit 69% of GDP, the highest level since 1955.
On 22 September 2008, the US federal debt hit $10 trillion, before the $750 billion Wall Street bailout. (See How Much Is A Million? A Trillion?)
Image from zFacts is used by permission.