context: Watson is the only golfer to score a round of 67 or less in all 4 majors at least once in 4 different decades. His best round in the Masters is a 67. His first 67 came in 1977. Other 67s were scored in the 1980s, 1990s and 2010s. His most recent 67 at Augusta was his opening round in 2010. His US Open low score is a 65. He scored 65 in 1987 and 2003, 66 in 1993 and he first shot 67 in 1975. At the British Open, Watsons low score is a 64 in 1980. 65s were scored in 1977 (twice), 1994 and 2009 (all 65s at the Open were scored at Turnberry). Finally at the PGA Championship, Watsons low score of the 1970s was a 66 in 1979. In the 1980s he scored a 67 in 1980, 1983, 1985, and 1989. His low PGA score is a 65 in 1993 & 2000.
question: Which years did Watson score his lowest score of 65 in golf?
answer: 1993