| Year | Value | | 2014 | 4,924.5440194404 | | 2013 | 4,915.8737648691 | | 2012 | 5,002.0474825488 | | 2011 | 4,867.0567999462 | | 2010 | 4,767.0973780964 | | 2009 | 4,434.1866334365 | | 2008 | 4,836.5939630514 | | 2007 | 4,873.0834669211 | | 2006 | 4,897.510041746 | | 2005 | 4,912.9097599509 | | 2004 | 4,797.2925825134 | | 2003 | 4,872.2722049666 | | 2002 | 4,500.3523003063 | | 2001 | 4,292.3150513449 | | 2000 | 4,311.8586366631 | | 1999 | 4,197.8646878822 | | 1998 | 3,921.7518369423 | | 1997 | 3,827.15372096 | | 1996 | 3,790.4212895329 | | 1995 | 3,921.3712081268 | | 1994 | 3,735.3554057263 | | 1993 | 3,716.5910780269 | | 1992 | 3,726.6945579379 | | 1991 | 3,597.6858277563 | | 1990 | 2,823.5028376203 | | 1989 | 2,851.2611127902 | | 1988 | 2,692.0031670625 | | 1987 | 2,487.7716010857 | | 1986 | 2,250.665700147 | | 1985 | 2,110.2564407404 | | 1984 | 1,920.7908213422 | | 1983 | 1,860.6818264332 | | 1982 | 1,831.8615026787 | | 1981 | 1,749.3150083704 | | 1980 | 1,664.3244011432 | | 1979 | 1,598.8919455419 | | 1978 | 1,479.7763893456 | | 1977 | 1,358.4389354008 | | 1976 | 1,249.2886903399 | | 1975 | 1,111.0307604315 | | 1974 | 1,006.6358494815 | | 1973 | 1,207.8093977498 | | 1972 | 1,071.2514465201 | | 1971 | 1,007.5982821275 |
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