1970 325.27
1971 326.16
1972 327.29
1973 329.51
1974 330.08
1975 330.99
1976 331.98
1977 333.73
1978 335.34
1979 336.68
1980 338.52
1981 339.76
1982 340.96
1983 342.61
1984 344.25
1985 345.73
1986 346.99
1987 348.79
1988 351.35
1989 352.75
1990 353.95