| Year | Value | | 2014 | 4,183.8274901981 | | 2013 | 4,270.8104093106 | | 2012 | 4,340.367988858 | | 2011 | 4,528.0500425936 | | 2010 | 4,492.7750300131 | | 2009 | 4,368.1179838986 | | 2008 | 4,592.6287112724 | | 2007 | 4,766.6523708832 | | 2006 | 4,626.305843745 | | 2005 | 4,529.4149820674 | | 2004 | 4,470.37817372 | | 2003 | 4,428.504644765 | | 2002 | 4,385.2782351815 | | 2001 | 4,151.0520262731 | | 2000 | 4,399.3939666589 | | 1999 | 4,275.5820966395 | | 1998 | 4,388.8875391405 | | 1997 | 4,574.026287882 | | 1996 | 4,450.8926381348 | | 1995 | 3,916.5114130187 | | 1994 | 3,814.2291914608 | | 1993 | 3,749.7084098366 | | 1992 | 3,701.4656463946 | | 1991 | 3,806.1684156561 | | 1990 | 3,911.6726520698 | | 1989 | 3,968.8187992123 | | 1988 | 3,994.239374049 | | 1987 | 3,964.5527230528 | | 1986 | 4,039.069628005 | | 1985 | 3,986.7609849019 | | 1984 | 3,920.8736687973 | | 1983 | 3,685.9046377149 | | 1982 | 3,644.8159406793 | | 1981 | 3,569.429662277 | | 1980 | 3,410.9604379296 | | 1979 | 3,228.5589016335 | | 1978 | 3,018.1318015728 | | 1977 | 2,880.6053918409 | | 1976 | 2,815.3004308864 | | 1975 | 2,687.0236920185 | | 1974 | 2,574.5487421629 | | 1973 | 2,455.4482960801 | | 1972 | 2,347.1942768378 | | 1971 | 2,204.2910819171 |
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