Year Measure 1971 113.37792 1972 112.05423 1973 119.67791 1974 177.02162 1975 270.82436 1976 407.21384 1977 761.66078 1978 537.90085 1979 772.21934 1980 996.95681 1981 802.92433 1982 1151.77841 1983 1004.65433 1984 1571.03426 1985 1408.4931 1986 1273.04515 1987 1413.00134 1988 1315.75588 1989 1472.53727 1990 2328.29772 1991 3083.71973 1992 2751.75177 1993 2863.3828 1994 2811.08373 1995 2767.63147 1996 2803.86298 1997 2998.06114 1998 3016.57552 1999 3122.25101 2000 3337.2822 2001 3345.71139 2002 3458.45387 2003 3606.03374 2004 3602.62456 2005 3944.38031 2006 5973.86015 2007 6646.33715 2008 5673.57034 2009 5486.31294 2010 6154.42419 2011 6800.14104 2012 6832.83275 2013 6583.46358 2014 6141.7732