| Year | Value | | 2021 | 4,262.7264124569 | | 2020 | 4,571.2197528134 | | 2019 | 4,842.4081891659 | | 2018 | 4,521.6446632917 | | 2017 | 4,141.3288887995 | | 2016 | 3,643.1534614806 | | 2015 | 3,788.0311339602 | | 2014 | 3,795.7975000632 | | 2013 | 3,943.6491919885 | | 2012 | 4,114.2715777157 | | 2011 | 3,618.7571600716 | | 2010 | 3,225.6593889434 | | 2009 | 2,770.7189953284 | | 2008 | 3,019.7110438262 | | 2007 | 2,617.4370234464 | | 2006 | 2,581.5773043453 | | 2005 | 2,262.2229226742 | | 2004 | 2,033.4306290709 | | 2003 | 1,789.6184809587 | | 2002 | 1,651.304389014 | | 2001 | 1,613.0156886591 | | 2000 | 1,852.4562437304 | | 1999 | 1,860.4585925808 | | 1998 | 1,809.5589111548 | | 1997 | 2,024.1870630355 | | 1996 | 2,086.8405904157 | | 1995 | 1,950.5212982073 | | 1994 | 1,907.2234922138 | | 1993 | 1,312.3661293897 | | 1992 | 1,303.8452731801 | | 1991 | 1,270.5912814741 | | 1990 | 1,098.5899819743 | | 1989 | 1,048.9780711501 | | 1988 | 1,089.7451198195 | | 1987 | 815.83305359579 | | 1986 | 692.61645365019 | | 1985 | 602.86766628675 | | 1984 | 641.63823775346 | | 1983 | 605.67186983666 | | 1982 | 632.19914050385 | | 1981 | 639.32983959672 |
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