| Year | Value | | 2021 | 28,072.203759317 | | 2020 | 25,451.517169755 | | 2019 | 25,831.455150068 | | 2018 | 27,237.403076899 | | 2017 | 25,890.446315771 | | 2016 | 23,960.529116158 | | 2015 | 23,450.989904591 | | 2014 | 23,855.823520916 | | 2013 | 22,213.541075093 | | 2012 | 20,885.063456583 | | 2011 | 20,578.172963589 | | 2010 | 18,937.431673049 | | 2009 | 15,514.211524278 | | 2008 | 17,500.411678004 | | 2007 | 19,974.030885178 | | 2006 | 17,949.260053462 | | 2005 | 15,951.376789581 | | 2004 | 13,671.446823189 | | 2003 | 12,133.244970774 | | 2002 | 10,921.417957845 | | 2001 | 9,481.9976496536 | | 2000 | 10,066.420098535 | | 1999 | 8,686.6189108699 | | 1998 | 6,659.1534576823 | | 1997 | 10,379.690776286 | | 1996 | 11,335.620482459 | | 1995 | 10,703.034359358 | | 1994 | 9,013.013682389 | | 1993 | 7,693.6717593376 | | 1992 | 7,058.1654475305 | | 1991 | 6,701.8529953833 | | 1990 | 5,772.2237559898 | | 1989 | 5,105.1823526379 | | 1988 | 4,153.8666340853 | | 1987 | 3,106.4719314848 | | 1986 | 2,461.9590989493 | | 1985 | 2,160.8594465918 | | 1984 | 2,129.1368066103 | | 1983 | 1,940.4585282402 | | 1982 | 1,761.8785830434 | | 1981 | 1,671.6472747838 | | 1980 | 1,533.7148958201 | | 1979 | 1,633.3230320397 | | 1978 | 1,302.2109377114 | | 1977 | 968.734621969 | | 1976 | 766.10084793999 | | 1975 | 564.89012252949 | | 1974 | 523.09749794121 | | 1973 | 376.66930961348 | | 1972 | 302.6492782255 | | 1971 | 283.33126428918 |
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