| Year | Value | | 2014 | 10,121.059099113 | | 2013 | 9,698.7626972908 | | 2012 | 9,067.1217851926 | | 2011 | 8,612.5736601695 | | 2010 | 8,645.3075724714 | | 2009 | 8,695.6298951349 | | 2008 | 8,474.4440515071 | | 2007 | 8,528.0978381404 | | 2006 | 8,374.2838136521 | | 2005 | 8,426.116051342 | | 2004 | 8,572.3559552906 | | 2003 | 8,532.8136253866 | | 2002 | 7,359.0569355586 | | 2001 | 7,166.5864509843 | | 2000 | 7,528.6141240874 | | 1999 | 7,356.7857634271 | | 1998 | 7,730.7029161149 | | 1997 | 7,592.2289800935 | | 1996 | 6,793.0345269043 | | 1995 | 6,342.4240296626 | | 1994 | 5,532.0533680443 | | 1993 | 5,212.2663875552 | | 1992 | 4,758.1970758716 | | 1991 | 4,413.3995405025 | | 1990 | 4,272.1663968724 | | 1989 | 4,258.9068674381 | | 1988 | 4,260.7913595872 | | 1987 | 4,189.9441340782 | | 1986 | 3,233.0352674978 | | 1985 | 3,300.0328652659 | | 1984 | 3,344.4816053512 | | 1983 | 3,146.6391677067 | | 1982 | 2,706.4746049943 | | 1981 | 2,333.8605556958 | | 1980 | 1,745.4142964331 | | 1979 | 1,313.5404586949 | | 1978 | 1,356.597947507 | | 1977 | 1,401.2664165103 | | 1976 | 1,447.9232297775 | | 1975 | 1,496.996611401 | | 1974 | 1,548.790129217 | | 1973 | 1,576.4934760004 | | 1972 | 1,654.0872635281 | | 1971 | 1,716.35440555 |
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