| Year | Value | | 2021 | 4,392.1898478958 | | 2020 | 4,306.9709384108 | | 2019 | 4,621.7660804978 | | 2018 | 4,678.0335810807 | | 2017 | 4,840.3517479292 | | 2016 | 4,803.8975980461 | | 2015 | 4,875.5073606223 | | 2014 | 4,832.4548057232 | | 2013 | 4,592.0171157307 | | 2012 | 4,220.1340373033 | | 2011 | 3,793.5220920955 | | 2010 | 3,504.4219269899 | | 2009 | 3,322.5856276626 | | 2008 | 3,018.6272644986 | | 2007 | 2,521.3217440917 | | 2006 | 2,324.4654126696 | | 2005 | 2,139.9615729263 | | 2004 | 2,007.8079806478 | | 2003 | 1,897.5891343437 | | 2002 | 1,726.4874369737 | | 2001 | 1,472.1246723964 | | 2000 | 1,010.2187159187 | | 1999 | 1,193.3571606842 | | 1998 | 1,883.8802783255 | | 1997 | 1,886.7352563613 | | 1996 | 1,666.6675608958 | | 1995 | 1,677.5231259167 | | 1994 | 1,610.1417979702 | | 1993 | 1,367.1831812264 | | 1992 | 1,335.3048748155 | | 1991 | 1,252.7598746715 | | 1990 | 1,051.9648947395 | | 1989 | 988.23281261907 | | 1988 | 984.08426967286 | | 1987 | 1,142.3370094792 | | 1986 | 1,304.60354708 | | 1985 | 1,442.7683777629 | | 1984 | 1,448.1140843964 | | 1983 | 1,530.0931637826 | | 1982 | 1,923.9734269442 | | 1981 | 2,162.9149708805 | | 1980 | 1,763.4207860464 | | 1979 | 1,436.4142484527 | | 1978 | 1,345.6168093179 | | 1977 | 1,296.6158375655 | | 1976 | 1,085.1878370384 | | 1975 | 962.245721822 | | 1974 | 808.14892232993 | | 1973 | 503.8990510246 | | 1972 | 440.11261928591 | | 1971 | 395.98475824475 | | 1970 | 424.50412659366 |
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