Thomas Clifton, 43, one of the top jockeys at Penn National for a 10-year period, died Friday following a two-year battle with cancer. Clifton, a native of St. Louis, won 2,016 races during his career. He collected his 2,000th win at Penn National on July 15, 2010, his last season as a jockey. He became ill during the winter of 2010-2011. Between 1999 and 2007, Clifton led the Penn National rider standings three times (1999, 2005, 2007) and was the runner-up in both 2003 and 2004. His best season came in 2003, when he won 204 races.