| Year | Value | | 2014 | 3,074.7020705656 | | 2013 | 2,967.3765580522 | | 2012 | 3,000.6035232656 | | 2011 | 2,929.0750285557 | | 2010 | 2,877.6526533134 | | 2009 | 2,716.5982152641 | | 2008 | 2,759.5132702877 | | 2007 | 2,443.8441351515 | | 2006 | 2,362.8531059886 | | 2005 | 2,397.4865333823 | | 2004 | 2,282.8225631851 | | 2003 | 2,169.4875438644 | | 2002 | 2,003.6675174161 | | 2001 | 2,108.9904020206 | | 2000 | 2,077.5395733577 | | 1999 | 2,023.4615794803 | | 1998 | 1,958.0387542418 | | 1997 | 1,839.8216817855 | | 1996 | 1,721.1386856875 | | 1995 | 1,643.330259076 | | 1994 | 1,572.834183119 | | 1993 | 1,494.3909644156 | | 1992 | 1,408.7404226936 | | 1991 | 1,346.5027221998 | | 1990 | 1,303.2185490521 | | 1989 | 1,319.6328046408 | | 1988 | 1,451.3048458997 | | 1987 | 1,412.3962129842 | | 1986 | 1,328.2349094386 | | 1985 | 1,285.8604676471 | | 1984 | 1,296.6527406614 | | 1983 | 1,254.2406702192 | | 1982 | 1,203.3083147453 | | 1981 | 1,192.008017903 | | 1980 | 1,237.9391212848 | | 1979 | 1,212.1823364112 | | 1978 | 1,089.9899842044 | | 1977 | 1,079.6300635852 | | 1976 | 1,031.4847816056 | | 1975 | 1,011.6110346297 | | 1974 | 993.72276840083 | | 1973 | 963.64641790193 | | 1972 | 926.83504359562 | | 1971 | 875.76551562026 |
|