(80) sets including 1971, 1972, (2) 1973, 1974, 1975, (2) 1976, 1978, (2) 1980, (3) 1981, 1982, (4) 1983, (3) 1984, (4) 1985, 1986, (4) 1987, (8) 1988, (7) 1989, (5) 1990, (9) 1991, (4) 1992, (4) 1993, (6) 1994, (3) 1996, 1997, 1998 and 2000