Year | Value | 1992 | 0.021000000000001 | 1991 | 0.16800000000001 | 1990 | 0.483 | 1989 | 0.90600000000001 | 1988 | 1.691 | 1987 | 3.14 | 1986 | 5.752 | 1985 | 7.08 | 1984 | 7.347 | 1983 | 7.624 | 1982 | 7.91 | 1981 | 8.206 | 1980 | 8.522 | 1979 | 8.855 | 1978 | 9.199 | 1977 | 9.555 | 1976 | 9.923 | 1975 | 10.305 | 1974 | 10.699 | 1973 | 11.106 | 1972 | 11.526 | 1971 | 11.961 | 1970 | 12.271 | 1969 | 12.524 | 1968 | 12.78 | 1967 | 13.042 | 1966 | 13.308 | 1965 | 13.578 | 1964 | 13.853 | 1963 | 14.133 | 1962 | 14.418 | 1961 | 14.707 | 1960 | 14.8 |
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