Year Measure 1971 2757.82284 1972 2772.88563 1973 2685.52054 1974 2682.52039 1975 2294.99748 1976 2513.20811 1977 2808.50599 1978 3328.18874 1979 3398.71792 1980 3527.04394 1981 3686.28623 1982 3648.18389 1983 3721.30264 1984 4142.43897 1985 4347.69004 1986 4493.9441 1987 4188.6313 1988 4558.47698 1989 4394.35196 1990 4900.00655 1991 4838.27151 1992 5286.2826 1993 5030.99549 1994 5036.34755 1995 4899.90446 1996 5779.2626 1997 5437.90881 1998 6304.78194 1999 7348.545 2000 7759.75328 2001 8635.7629 2002 9356.80294 2003 10413.69275 2004 10876.63721 2005 12426.38793 2006 13798.83727 2007 14608.00987 2008 14117.1889 2009 14203.1525 2010 15109.18756 2011 14791.36387 2012 14346.84046 2013 14537.4842 2014 14446.74945