| Year | Value | | 2021 | 8,167.6967426546 | | 2020 | 8,094.4822977542 | | 2019 | 10,263.538099246 | | 2018 | 10,358.52682684 | | 2017 | 9,572.1364581317 | | 2016 | 8,599.2419640184 | | 2015 | 8,194.7574385544 | | 2014 | 8,839.1615779416 | | 2013 | 8,304.5448297267 | | 2012 | 7,767.9034933293 | | 2011 | 7,760.7265818355 | | 2010 | 6,872.940220454 | | 2009 | 6,321.8874133866 | | 2008 | 7,248.6408731426 | | 2007 | 6,094.6494443337 | | 2006 | 5,168.706549839 | | 2005 | 4,751.5263384678 | | 2004 | 4,863.4802883024 | | 2003 | 4,304.0698676699 | | 2002 | 3,624.2794145805 | | 2001 | 3,452.2128509705 | | 2000 | 3,468.999390439 | | 1999 | 3,241.5300030746 | | 1998 | 3,134.2776403438 | | 1997 | 3,191.6613741933 | | 1996 | 3,443.8754311165 | | 1995 | 3,216.227570659 | | 1994 | 2,898.7064335443 | | 1993 | 2,757.9457016003 | | 1992 | 2,793.5900952463 | | 1991 | 2,532.7251680167 | | 1990 | 2,366.8698731255 | | 1989 | 1,967.7121849566 | | 1988 | 1,927.9052890516 | | 1987 | 1,717.2291293472 | | 1986 | 1,317.8789234885 | | 1985 | 968.95679728898 | | 1984 | 943.90448824148 | | 1983 | 998.18153593179 | | 1982 | 988.96474500176 | | 1981 | 1,061.3605638912 | | 1980 | 1,087.793186314 | | 1979 | 1,193.9311900679 | | 1978 | 1,031.10841274 | | 1977 | 852.47325219542 | | 1976 | 751.03175032854 |
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