| Year | Value | | 2021 | 6.39867 | | 2020 | 21.804 | | 2019 | 108.9135 | | 2018 | 106.8282 | | 2017 | 102.59573 | | 2016 | 86.955 | | 2015 | 83.686504302051 | | 2014 | 78.513996 | | 2013 | 69.333 | | 2012 | 90.940552146248 | | 2011 | 84.640733279789 | | 2010 | 77.084703141 | | 2009 | 65.564 | | 2008 | 96.057 | | 2007 | 101.54 | | 2006 | 95.792 | | 2005 | 92.108 | | 2004 | 74.769 | | 2003 | 68 | | 2002 | 67.15 | | 2001 | 84.478 | | 2000 | 90.819 | | 1999 | 83.5999984741 | | 1998 | 17.5 | | 1997 | 17.5 | | 1996 | 75.4000015259 | | 1995 | 82.5999984741 | | 1994 | 55.9000015259 | | 1993 | 37.7000007629 | | 1992 | 33.7999992371 | | 1991 | 23.2999992371 | | 1990 | 5.0999999046 | | 1989 | 20.3999996185 | | 1988 | 15 | | 1987 | 10.3000001907 | | 1986 | 6 | | 1985 | 3.7999999523 | | 1984 | 3.7000000477 | | 1983 | 3.4000000954 | | 1982 | 3.4000000954 | | 1981 | 3.0999999046 | | 1980 | 2.7999999523 | | 1979 | 2.7999999523 | | 1978 | 2.0999999046 | | 1977 | 1.2000000477 | | 1976 | 1 | | 1975 | 1 | | 1974 | 0.8999999762 | | 1973 | 0.6999999881 |
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