Year Measure 1971 1059.38591 1972 1159.68999 1973 1230.65333 1974 1177.61561 1975 969.00823 1976 935.07896 1977 899.76767 1978 859.80425 1979 897.98326 1980 713.85257 1981 744.37049 1982 796.46299 1983 830.94754 1984 744.2929 1985 702.85805 1986 698.77465 1987 730.83536 1988 666.24378 1989 614.21473 1990 603.34786 1991 640.53431 1992 715.1926 1993 710.71217 1994 733.20634 1995 728.8627 1996 763.30881 1997 777.41481 1998 883.48359 1999 853.57686 2000 847.75671 2001 942.63912 2002 840.29607 2003 825.54857 2004 799.27611 2005 875.05589 2006 918.0319 2007 882.48243 2008 869.00487 2009 942.16241 2010 990.52789 2011 1056.0985 2012 1071.56386 2013 1034.76288 2014 1079.13015