| Year | Value | | 2021 | 4,823.4817941724 | | 2020 | 4,181.9315794487 | | 2019 | 4,787.3975295769 | | 2018 | 4,660.2426282103 | | 2017 | 4,772.055405086 | | 2016 | 4,869.3481886971 | | 2015 | 4,912.6127293335 | | 2014 | 4,621.4955229873 | | 2013 | 4,459.9871387789 | | 2012 | 4,175.9997569229 | | 2011 | 4,021.2373952325 | | 2010 | 3,887.5617897316 | | 2009 | 4,049.7995610668 | | 2008 | 3,966.3668290714 | | 2007 | 4,151.8417663334 | | 2006 | 4,117.9875114391 | | 2005 | 4,018.3763768242 | | 2004 | 3,917.6238980356 | | 2003 | 3,846.156170678 | | 2002 | 3,835.3484670413 | | 2001 | 3,720.643534773 | | 2000 | 3,737.1623089789 | | 1999 | 3,772.5840280908 | | 1998 | 3,731.682354711 | | 1997 | 3,690.841599198 | | 1996 | 3,727.1399771432 | | 1995 | 3,684.5352182187 | | 1994 | 3,554.3393105457 | | 1993 | 3,521.8969881492 | | 1992 | 3,326.4120688201 | | 1991 | 2,935.6279542575 | | 1990 | 2,759.0613873315 | | 1989 | 1,868.1923313412 | | 1988 | 1,660.39138019 | | 1987 | 1,486.5658175367 | | 1986 | 1,249.6257330158 | | 1985 | 1,138.0253702662 | | 1984 | 1,188.1118407421 | | 1983 | 1,092.8862203708 | | 1982 | 1,056.0967547342 | | 1981 | 1,209.9357479485 | | 1980 | 1,256.5228058375 |
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