1971 220.0 1972 509.0 1973 238.5 1974 233.0 1975 228.5 1976 241.5 1977 288.5 1978 388.5 1979 312.5 1980 307.0 1981 372.5 1982 317.5 1983 268.5 1984 281.0 1985 319.5 1986 306.0 1987 305.0 1988 291.0 1989 231.5 1990 333.0 1991 446.0 1992 239.0 1993 296.0 1994 422.0 1995 279.5 1996 415.0 1997 266.5 1998 253.5 1999 353.0 2000 331.0