A close-up of the front of the United States 100-dollar bill bearing the portrait of US statesman, inventor and diplomat Benjamin Franklin is seen December 7, 2010 in Washington, DC. More than one billion US 100 dollar bills, approximately 10 per cent of the total stock of US currency on the planet, are being kept from circulation following printing errors that left the notes unusable. To correct matters attempts are being made to create a new machine that will successfully identify and separate the defective bills from the properly-printed currency, a project if performed by hand would take between 20 and 30 years, they estimate, adding that a mechanized process would be complete by 2012. The distressing muddle comes after the US Federal Reserve announced in April 2010 that the new notes, carrying an array of new security measures to circumvent counterfeiters, would be released in February 2011. AFP PHOTO / Paul J. RICHARDS (Photo credit should read PAUL J. RICHARDS/AFP/Getty Images)