1950 1951 1952 1953 1954 1955 1956 1957 | 5.55 9.05 9.45 10.75 11.15 11.55 9.70 10.75 | 1958 1959 1960 1961 1962 1963 1964 1965 | 12.05 13.15 13.80 14.70 14.20 13.45 12.55 12.70 | 1966 1967 1968 1969 1970 1971 1972 1973 | 12.55 14.20 12.15 12.45 15.95 17.25 17.25 17.00 | 1974 1975 1976 1977 1978 1979 1980 1981 | 19.50 16.15 14.60 16.75 16.80 18.37 18.27 17.80 | 1982 1983 1984 1985 1986 1987 1988 1989 | 17.20 17.68 20.43 19.64 21.49 18.92 17.43 20.12 | 1990 1991 1992 1993 1994 1995 1996 | 20.64 20.02 21.16 19.46 19.83 21.02 |