| Year | Value | | 2014 | 5,137.073835194 | | 2013 | 5,202.4672880761 | | 2012 | 5,137.789017969 | | 2011 | 5,347.5262226622 | | 2010 | 5,201.4048968103 | | 2009 | 4,954.138250997 | | 2008 | 5,294.4350988329 | | 2007 | 5,272.3707825406 | | 2006 | 5,153.1214836106 | | 2005 | 4,932.8032814132 | | 2004 | 5,097.8355558534 | | 2003 | 5,021.7982221226 | | 2002 | 5,051.5983895589 | | 2001 | 5,027.4528074407 | | 2000 | 4,955.9078964949 | | 1999 | 5,028.706342823 | | 1998 | 4,682.2975759649 | | 1997 | 5,068.089389929 | | 1996 | 5,150.4077243275 | | 1995 | 4,925.9613811938 | | 1994 | 4,582.5819613488 | | 1993 | 4,570.4424441417 | | 1992 | 4,699.1375709329 | | 1991 | 5,115.1227897228 | | 1990 | 5,542.1709028196 | | 1989 | 5,266.1685818381 | | 1988 | 5,150.4629188763 | | 1987 | 5,085.1643933186 | | 1986 | 4,941.6250564611 | | 1985 | 4,841.3644317218 | | 1984 | 4,624.05918983 | | 1983 | 4,520.842714933 | | 1982 | 4,439.2800220134 | | 1981 | 4,411.7896256159 | | 1980 | 4,358.5956506416 | | 1979 | 3,806.4593590611 | | 1978 | 3,468.6229902099 | | 1977 | 3,413.4896367132 | | 1976 | 3,260.4608365746 | | 1975 | 3,111.7689943565 | | 1974 | 3,138.2053525411 | | 1973 | 3,026.212741937 | | 1972 | 2,829.4691188442 | | 1971 | 2,696.6840440782 |
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