World No. 1 July 10, 1978 - January 13, 1979 January 28, 1979 - February 24, 1979 April 16, 1979 - June 24, 1979 September 10, 1979 - April 6, 1980 April 21, 1980 - June 30, 1980 May 3, 1982 - May 16, 1982 June 14, 1982 - June 9, 1985 October 14, 1985 - October 27, 1985 November 25, 1985 - August 16, 1987
