The U.S. GAO's 2010 findings regarding the great difficulty of accurately gauging the economic impact of copyright infringement was reinforced within the same report by the body's research into <answer>three</answer> commonly cited estimates that had previously been provided to U.S. agencies. The GAO report explained that the sources – a Federal Bureau of Investigation (FBI) estimate, a Customs and Border Protection (CBP) press release and a Motor and Equipment Manufacturers Association estimate – "cannot be substantiated or traced back to an underlying data source or methodology."
How many commanly cited estimates did the body report on?
three