Even during his retirement, Alan Greenspan found reading government reports relaxing, he told Lesley Stahl in 2007. "I just love getting into the detail of, say, protein content of hard red winter wheat was because the differential in price," said the former chairman of the Federal Reserve. "It makes your head hurt," said his wife, former NBC News correspondent Andrea Mitchell. Greenspan, one of the longest-serving Federal Reserve chairs in U.S. history, died on Monday. He was 100. #federalreserve #greenspan