| Year | Value | | 2014 | 4,708.9274575723 | | 2013 | 4,639.7063226115 | | 2012 | 4,761.9125833848 | | 2011 | 4,863.6914411006 | | 2010 | 4,560.4149170338 | | 2009 | 4,483.7471386375 | | 2008 | 4,674.5031505249 | | 2007 | 4,523.3228783124 | | 2006 | 4,366.9127651518 | | 2005 | 4,165.1803923555 | | 2004 | 3,971.8227361906 | | 2003 | 3,997.9025962509 | | 2002 | 3,853.8190041011 | | 2001 | 3,859.0900248741 | | 2000 | 3,673.6068714343 | | 1999 | 3,613.3672666048 | | 1998 | 3,932.4017844231 | | 1997 | 3,970.1311394469 | | 1996 | 4,350.4432592523 | | 1995 | 4,211.1251314081 | | 1994 | 3,825.3866157184 | | 1993 | 3,807.696906382 | | 1992 | 3,735.5254536096 | | 1991 | 4,361.144515751 | | 1990 | 4,758.7319025556 | | 1989 | 4,963.1788857732 | | 1988 | 4,940.5184866668 | | 1987 | 4,838.6203249697 | | 1986 | 4,646.2609387564 | | 1985 | 4,678.285823399 | | 1984 | 4,772.2945995499 | | 1983 | 4,582.125337454 | | 1982 | 4,397.890564541 | | 1981 | 4,125.3534285962 | | 1980 | 3,973.6907883341 | | 1979 | 3,772.289410533 | | 1978 | 3,648.387026505 | | 1977 | 3,437.7976923015 | | 1976 | 3,247.5513492512 | | 1975 | 3,035.6361878381 | | 1974 | 2,842.2312212192 | | 1973 | 2,683.1096789954 | | 1972 | 2,486.0660898766 | | 1971 | 2,292.6539833267 |
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