Year Measure 1971 1558.76546 1972 1546.17922 1973 1605.30091 1974 1563.19027 1975 1656.63669 1976 1681.12434 1977 1638.68638 1978 1630.66991 1979 1723.16665 1980 1717.75899 1981 1780.18066 1982 1876.17261 1983 1941.87539 1984 1945.58945 1985 2019.39948 1986 2099.72004 1987 2084.45401 1988 2239.64166 1989 2631.39908 1990 2537.37485 1991 2978.22813 1992 3267.64015 1993 3375.75533 1994 3445.39221 1995 3482.93363 1996 3521.82213 1997 3530.10394 1998 3636.24558 1999 3743.02217 2000 3880.69275 2001 3888.57015 2002 3962.71874 2003 4098.36066 2004 4138.44996 2005 4394.57691 2006 4520.68368 2007 4613.96493 2008 4918.73396 2009 5128.04952 2010 5182.43997 2011 4969.31597 2012 5085.80436 2013 5409.24005 2014 5640.75445