Year Measure 1971 2288.69339 1972 2497.14104 1973 2497.55949 1974 2518.21143 1975 2624.89146 1976 2718.08661 1977 2831.99557 1978 3011.92412 1979 3049.3925 1980 3022.17638 1981 3067.49242 1982 3173.90226 1983 3313.27649 1984 3359.46141 1985 3485.23506 1986 3407.07141 1987 3756.46601 1988 4026.11436 1989 4228.41965 1990 4176.18026 1991 3981.20832 1992 4568.41694 1993 4618.89375 1994 4934.24708 1995 5127.86294 1996 5340.30218 1997 5488.51953 1998 5819.46073 1999 5974.36735 2000 6323.10383 2001 6400.21743 2002 6502.73973 2003 6597.30631 2004 6525.92157 2005 6572.19954 2006 6711.22957 2007 7003.24508 2008 7134.00285 2009 6607.88714 2010 6953.27667 2011 6930.00077 2012 7184.50161 2013 6710.09368 2014 6600.89828