| Year | Value | | 2021 | 51,245.331167745 | | 2020 | 42,913.291089109 | | 2019 | 57,488.78007241 | | 2018 | 56,371.892109622 | | 2017 | 52,271.570608362 | | 2016 | 46,422.626273609 | | 2015 | 43,811.498408553 | | 2014 | 42,162.85953715 | | 2013 | 39,171.579558072 | | 2012 | 37,453.668404532 | | 2011 | 38,037.121912316 | | 2010 | 38,092.248462685 | | 2009 | 30,565.418 | | 2008 | 28,361.424 | | 2007 | 27,013.364 | | 2006 | 23,640.413 | | 2005 | 22,669.605 | | 2004 | 21,915.981 | | 2003 | 18,837.049 | | 2002 | 17,520.666 | | 2001 | 16,509.922 | | 2000 | 16,912.116 | | 1999 | 15,001.318944577 | | 1998 | 14,142.973841006 | | 1997 | 14,292.300046213 | | 1996 | 12,366.899990245 | | 1995 | 11,988.70010604 | | 1994 | 11,433.099896118 | | 1993 | 10,117.50008405 | | 1992 | 8,566.9000720451 | | 1991 | 7,662.4999406335 | | 1990 | 7,463.0000555589 | | 1989 | 7,087.2000016347 | | 1988 | 6,764.3999933824 | | 1987 | 6,304.8000331001 | | 1986 | 5,490.2000451163 | | 1985 | 5,182.000037469 | | 1984 | 5,331.1000511352 | | 1983 | 4,793.3999606667 | | 1982 | 4,455.4000314773 | | 1981 | 4,209.6000072508 | | 1980 | 3,793.4999789146 | | 1979 | 3,409.8000349551 | | 1978 | 3,252.5999953673 | | 1977 | 2,955.9999815375 | | 1976 | 2,665.2000201272 | | 1975 | 2,262.6999936851 | | 1974 | 1,984.9999930412 |
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