Year Measure 1990 4856.58585 1991 4852.50299 1992 4209.62162 1993 3728.58301 1994 3192.73706 1995 3177.8134 1996 2937.27091 1997 2836.2076 1998 2706.13513 1999 2718.99127 2000 2720.72429 2001 2754.42367 2002 2813.15969 2003 3025.13547 2004 3031.49955 2005 3033.18368 2006 2935.29231 2007 2996.21074 2008 2910.6609 2009 2487.03628 2010 2886.99457 2011 2768.92413 2012 2687.05852 2013 2553.11651 2014 2334.4072