Year Measure 1971 2161.92157 1972 2303.49033 1973 2411.22595 1974 2529.89819 1975 2642.48931 1976 2770.92748 1977 2839.11863 1978 2980.30083 1979 3192.95046 1980 3376.92908 1981 3534.31247 1982 3609.00304 1983 3654.42026 1984 3900.00068 1985 3989.45774 1986 4084.43864 1987 4064.60369 1988 4152.28719 1989 4177.06346 1990 4152.97709 1991 4051.05852 1992 3927.21332 1993 3956.75839 1994 4003.8428 1995 4093.12214 1996 4633.81954 1997 4744.59734 1998 4535.28108 1999 4399.49821 2000 4503.77408 2001 4226.646 2002 4444.52497 2003 4470.82248 2004 4498.97865 2005 4547.65127 2006 4638.22422 2007 4777.05886 2008 4606.62949 2009 4385.25432 2010 4510.21653 2011 4543.62848 2012 4352.39203 2013 4279.24759 2014 4198.40119