| Year | Value | | 2014 | 6,258.8910370366 | | 2013 | 6,284.7908062489 | | 2012 | 6,304.5719230295 | | 2011 | 6,298.7276783503 | | 2010 | 6,348.4243981284 | | 2009 | 6,139.3520603726 | | 2008 | 6,489.1262574024 | | 2007 | 6,518.2174126998 | | 2006 | 6,528.5301504409 | | 2005 | 6,357.4210946081 | | 2004 | 6,230.3982278885 | | 2003 | 6,074.8491416224 | | 2002 | 5,894.2331191117 | | 2001 | 5,892.1725954953 | | 2000 | 5,703.8167391073 | | 1999 | 5,493.8515304565 | | 1998 | 5,604.8095401245 | | 1997 | 5,660.0600283517 | | 1996 | 5,729.3862547661 | | 1995 | 5,470.6706614043 | | 1994 | 5,186.9694424598 | | 1993 | 5,032.403649422 | | 1992 | 5,077.660184882 | | 1991 | 5,256.3020816256 | | 1990 | 5,600.4076120486 | | 1989 | 5,576.9347329831 | | 1988 | 5,504.9232874141 | | 1987 | 5,447.305282393 | | 1986 | 5,259.3121384785 | | 1985 | 5,141.6652107483 | | 1984 | 4,959.8202863774 | | 1983 | 4,812.1554581931 | | 1982 | 4,675.5999568 | | 1981 | 4,639.7337783822 | | 1980 | 4,585.1237452559 | | 1979 | 4,392.3923624373 | | 1978 | 4,499.9569424155 | | 1977 | 4,292.9274337117 | | 1976 | 4,173.4401125663 | | 1975 | 4,031.2687028638 | | 1974 | 3,860.3552359778 | | 1973 | 3,729.9947411206 | | 1972 | 3,595.7968436602 | | 1971 | 3,424.2020430831 |
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