| Year | Value | | 2021 | 50,689.992701189 | | 2020 | 40,860.480663045 | | 2019 | 46,216.418101957 | | 2018 | 48,006.33509651 | | 2017 | 47,208.510797801 | | 2016 | 44,514.645953087 | | 2015 | 43,257.862022732 | | 2014 | 47,257.567984784 | | 2013 | 45,715.855537849 | | 2012 | 45,310.399461819 | | 2011 | 44,678.099778417 | | 2010 | 40,278.664993194 | | 2009 | 30,670.109563693 | | 2008 | 32,449.60341974 | | 2007 | 32,959.45037083 | | 2006 | 27,931.842025741 | | 2005 | 23,539.883705654 | | 2004 | 21,398.133632543 | | 2003 | 19,054.059273429 | | 2002 | 18,040.140873817 | | 2001 | 18,081.471987259 | | 2000 | 20,280.949153528 | | 1999 | 18,719.43405832 | | 1998 | 18,971.848758599 | | 1997 | 23,608.052120803 | | 1996 | 22,712.226612994 | | 1995 | 21,917.986516692 | | 1994 | 18,683.653146839 | | 1993 | 15,241.773423849 | | 1992 | 13,795.029748103 | | 1991 | 12,202.454542902 | | 1990 | 10,038.869804408 | | 1989 | 8,777.9449012901 | | 1988 | 7,395.3160823085 | | 1987 | 6,065.8922600456 | | 1986 | 5,659.4439529276 | | 1985 | 5,975.0440495569 | | 1984 | 6,157.1260659218 | | 1983 | 5,486.684196816 | | 1982 | 4,876.3354788579 | | 1981 | 4,482.7449530521 | | 1980 | 4,009.0614376686 | | 1979 | 3,402.3574070847 | | 1978 | 2,788.2115599506 | | 1977 | 2,468.1277272843 | | 1976 | 2,428.7319407565 | | 1975 | 2,260.6321058738 | | 1974 | 2,061.2244389216 | | 1973 | 1,515.5101403687 | | 1972 | 1,167.4995337979 | | 1971 | 996.46371563509 |
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