Year Measure 1990 4787.48169 1991 4643.26572 1992 4313.53505 1993 3953.27948 1994 3475.16145 1995 3348.92838 1996 3060.37216 1997 2958.58579 1998 2839.48575 1999 2792.14106 2000 2778.43709 2001 2790.5344 2002 2844.81095 2003 2997.9744 2004 3151.1477 2005 3246.03573 2006 3399.52231 2007 3528.92483 2008 3534.35715 2009 3227.95543 2010 3549.84772 2011 3662.44331 2012 3640.55684 2013 3600.2295 2014 3418.58502