| Year | Value | | 2021 | 71.46695325094 | | 2020 | 71.46695325094 | | 2019 | 71.46695325094 | | 2018 | 71.46695325094 | | 2017 | 71.46695325094 | | 2016 | 71.46695325094 | | 2015 | 71.46695325094 | | 2014 | 71.46695325094 | | 2013 | 71.46695325094 | | 2012 | 71.46695325094 | | 2011 | 71.46695325094 | | 2010 | 71.46695325094 | | 2009 | 71.46695325094 | | 2008 | 71.46695325094 | | 2007 | 71.46695325094 | | 2006 | 71.46695325094 | | 2005 | 71.46695325094 | | 2004 | 71.46695325094 | | 2003 | 70.929607737775 | | 2002 | 70.39226222461 | | 2001 | 69.854916711445 | | 2000 | 68.780225685115 | | 1999 | 68.242880171951 | | 1998 | 67.705534658786 | | 1997 | 67.705534658786 | | 1996 | 66.630843632456 | | 1995 | 65.556152606126 | | 1994 | 64.481461579796 | | 1993 | 63.406770553466 | | 1992 | 61.794734013971 | | 1991 | 61.794734013971 | | 1990 | 61.257388500806 | | 1989 | 61.257388500806 | | 1988 | 61.257388500806 | | 1987 | 60.720042987641 | | 1986 | 59.108006448146 | | 1985 | 59.108006448146 | | 1984 | 59.108006448146 | | 1983 | 53.734551316496 | | 1982 | 53.734551316496 | | 1981 | 53.734551316496 | | 1980 | 53.734551316496 | | 1979 | 53.734551316496 | | 1978 | 53.734551316496 | | 1977 | 51.047823750672 | | 1976 | 51.047823750672 | | 1975 | 51.047823750672 | | 1974 | 51.047823750672 | | 1973 | 51.047823750672 | | 1972 | 51.047823750672 | | 1971 | 51.047823750672 | | 1970 | 51.047823750672 | | 1969 | 51.047823750672 | | 1968 | 51.047823750672 | | 1967 | 51.047823750672 | | 1966 | 51.047823750672 | | 1965 | 51.047823750672 | | 1964 | 51.047823750672 | | 1963 | 51.047823750672 | | 1962 | 51.047823750672 | | 1961 | 51.047823750672 |
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