premise: William Daniel "Dan" McCafferty (born 14 October 1946, Dunfermline, Scotland) is a Scottish vocalist, best known as the lead singer for the Scottish hard rock band Nazareth from its founding in 1968 to his retirement from touring with the band in 2013. McCafferty continues to perform solo around the world and record on occasion.
hypothesis: McCafferty was the lead singer of Nazareth for 47 years
reason: He was the lead singer for 45 years