| Year | Value | | 2014 | 1,642.1582734903 | | 2013 | 1,621.6438882939 | | 2012 | 1,591.5296406736 | | 2011 | 1,601.9290195562 | | 2010 | 1,576.4631883886 | | 2009 | 1,452.7914230109 | | 2008 | 1,420.3247630173 | | 2007 | 1,385.5937385349 | | 2006 | 1,352.4727975701 | | 2005 | 1,280.3263040799 | | 2004 | 1,256.3417761339 | | 2003 | 1,190.2316363851 | | 2002 | 1,144.5904196478 | | 2001 | 1,085.0588565234 | | 2000 | 1,037.7864252209 | | 1999 | 1,002.0413512897 | | 1998 | 964.35789437004 | | 1997 | 922.21059513048 | | 1996 | 892.37834324412 | | 1995 | 846.71451345446 | | 1994 | 824.70155760377 | | 1993 | 797.67145404084 | | 1992 | 778.24372714246 | | 1991 | 731.24777060573 | | 1990 | 722.35327426147 | | 1989 | 695.56816420977 | | 1988 | 675.70106034182 | | 1987 | 661.69364269146 | | 1986 | 636.01086076316 | | 1985 | 599.48940567426 | | 1984 | 584.6104741787 | | 1983 | 552.60536521283 | | 1982 | 501.36664991307 | | 1981 | 451.85384958783 | | 1980 | 433.75503207044 | | 1979 | 412.62187495148 | | 1978 | 367.94523654825 | | 1977 | 341.30971892716 | | 1976 | 315.13943458173 | | 1975 | 287.45852710085 | | 1974 | 263.2168933154 | | 1973 | 241.24037227162 | | 1972 | 215.21227714048 | | 1971 | 200.55777801896 |
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