| Year | Value | | 2021 | 4.29491 | | 2020 | 10.604353816 | | 2019 | 50.80511 | | 2018 | 64.20469 | | 2017 | 57.68029 | | 2016 | 60.17416 | | 2015 | 64.037777 | | 2014 | 82.101 | | 2013 | 112.059962 | | 2012 | 121.4025905791 | | 2011 | 126.4039 | | 2010 | 129.7315 | | 2009 | 3.229 | | 2008 | 4.662 | | 2007 | 5.615 | | 2006 | 5.874 | | 2005 | 5.439 | | 2004 | 4.99 | | 2003 | 4.291 | | 2002 | 7.989 | | 2001 | 6.354 | | 2000 | 15.456 | | 1999 | 33 | | 1998 | 82.1999969482 | | 1997 | 53.7999992371 | | 1996 | 32.9000015259 | | 1995 | 32.2000007629 | | 1994 | 38 | | 1993 | 85.4000015259 | | 1992 | 54.0999984741 | | 1991 | 68 | | 1990 | 63.2000007629 | | 1989 | 68.4000015259 | | 1988 | 73.5999984741 | | 1987 | 70 | | 1986 | 58.5999984741 | | 1985 | 50.7000007629 | | 1984 | 42.5 | | 1983 | 33 | | 1982 | 36.5999984741 | | 1981 | 38.7999992371 | | 1980 | 39.7999992371 | | 1979 | 30.8999996185 | | 1978 | 12.8999996185 | | 1977 | 9.5 | | 1976 | 6.9000000954 | | 1975 | 6.4000000954 | | 1974 | 9.8000001907 | | 1973 | 9.6000003815 | | 1972 | 4.5 | | 1971 | 4.6999998093 | | 1970 | 9.3000001907 |
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