| Year | Value | | 2022 | 69.159957339254 | | 2021 | 70.648568529739 | | 2020 | 73.184464699852 | | 2019 | 71.669745800707 | | 2018 | 68.860124751423 | | 2017 | 66.965379074285 | | 2016 | 70.370420480716 | | 2015 | 72.855404626663 | | 2009 | 82.058522616933 | | 2008 | 86.133709027311 | | 2007 | 82.424396873938 | | 2006 | 83.024214953653 | | 2005 | 82.102771465218 | | 2004 | 83.567377911568 | | 2003 | 84.008772719192 | | 2002 | 83.990276505561 | | 2001 | 81.639593064648 | | 2000 | 81.99277851461 | | 1999 | 80.615517318391 | | 1998 | 81.490600067191 | | 1997 | 82.1534855078 | | 1996 | 82.450633227795 | | 1995 | 83.479585846666 | | 1994 | 81.784024424781 | | 1993 | 81.384624623422 | | 1992 | 81.957731675143 | | 1991 | 82.26735957244 | | 1990 | 82.293774706014 | | 1989 | 83.124049688159 | | 1988 | 82.587281851682 | | 1987 | 82.781525291908 | | 1986 | 83.251780202146 | | 1985 | 83.282894534257 | | 1984 | 80.928284313088 | | 1983 | 81.403039448689 | | 1982 | 81.681210826498 | | 1981 | 80.904240927004 | | 1980 | 82.131781081366 | | 1979 | 82.850363639834 | | 1978 | 83.272987226064 | | 1977 | 82.466338890873 | | 1976 | 84.009601695196 | | 1975 | 83.443880046657 | | 1974 | 85.757014850027 | | 1973 | 85.277113670941 | | 1972 | 86.869941627861 | | 1971 | 87.088540925267 | | 1970 | 86.516539812646 | | 1969 | 87.321872595126 | | 1968 | 87.987076607576 | | 1967 | 88.675666703552 | | 1966 | 88.949406261245 | | 1965 | 89.476966848095 | | 1964 | 89.128376117028 | | 1963 | 87.115300753183 | | 1962 | 87.108042878049 | | 1961 | 85.755651469091 | | 1960 | 90.61136492326 |
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