Year Measure 1971 785.16153 1972 865.59248 1973 762.72536 1974 776.93475 1975 826.95208 1976 890.95336 1977 923.72887 1978 1010.81922 1979 864.19946 1980 1149.5361 1981 989.20015 1982 966.68328 1983 1000.12201 1984 1018.26314 1985 916.55519 1986 963.92717 1987 921.89304 1988 927.74452 1989 896.43776 1990 813.2557 1991 572.78184 1992 418.28663 1993 412.37888 1994 441.2493 1995 417.03484 1996 447.84887 1997 384.59496 1998 426.68282 1999 576.18363 2000 580.49476 2001 597.26525 2002 660.04798 2003 648.16839 2004 715.41448 2005 719.58438 2006 706.85941 2007 679.86177 2008 710.7485 2009 732.31668 2010 729.15437 2011 764.96862 2012 687.89626 2013 801.32998 2014 808.45584