| Year | Value | | 2014 | 1,922.8831976959 | | 2013 | 1,919.8440583237 | | 2012 | 1,922.9011232335 | | 2011 | 1,866.4825042105 | | 2010 | 1,869.6514166688 | | 2009 | 1,827.9131832184 | | 2008 | 1,872.7560967862 | | 2007 | 1,870.4874911571 | | 2006 | 1,809.2025621652 | | 2005 | 1,709.0345507192 | | 2004 | 1,668.5477802859 | | 2003 | 1,633.9549397055 | | 2002 | 1,550.2266396903 | | 2001 | 1,478.823513738 | | 2000 | 1,500.5555146483 | | 1999 | 1,429.4758588517 | | 1998 | 1,307.3670762787 | | 1997 | 1,352.3483983216 | | 1996 | 1,241.7148355384 | | 1995 | 1,271.5317941725 | | 1994 | 1,256.4657544297 | | 1993 | 1,319.9732657695 | | 1992 | 1,390.4529854401 | | 1991 | 1,108.8425252222 | | 1990 | 1,058.8132109745 | | 1989 | 1,062.682344046 | | 1988 | 1,127.1177603174 | | 1987 | 1,129.3871459125 | | 1986 | 1,062.9074785917 | | 1985 | 994.78145658087 | | 1984 | 978.04317187152 | | 1983 | 908.28253001298 | | 1982 | 923.63904374348 | | 1981 | 953.11634789996 | | 1980 | 922.00523298028 | | 1979 | 850.0556345876 | | 1978 | 842.00489018944 | | 1977 | 790.78732763308 | | 1976 | 759.84616690595 | | 1975 | 724.95679143879 | | 1974 | 713.23245402007 | | 1973 | 671.40287312579 | | 1972 | 647.90056183769 | | 1971 | 602.4709706605 |
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