Year Measure 1971 1021.59737 1972 1070.49494 1973 1117.63895 1974 1182.75098 1975 1150.0895 1976 1166.17338 1977 1104.62723 1978 1061.17575 1979 1039.57501 1980 1030.69501 1981 1066.42276 1982 1049.84229 1983 1028.59109 1984 988.31166 1985 943.89646 1986 897.40743 1987 882.38249 1988 933.54379 1989 780.54132 1990 762.77651 1991 737.40262 1992 735.65993 1993 739.51733 1994 729.30761 1995 707.33781 1996 681.58322 1997 633.72995 1998 577.67544 1999 579.99667 2000 591.00459 2001 611.13485 2002 635.49821 2003 653.82687 2004 674.5799 2005 681.45484 2006 692.61819 2007 652.52373 2008 579.01702 2009 558.24667 2010 580.14302 2011 621.04112 2012 721.49969 2013 735.88368 2014 707.19022