Year Measure 1971 425.63739 1972 443.19298 1973 470.50196 1974 449.01642 1975 474.43391 1976 466.44639 1977 529.17189 1978 557.84691 1979 561.28584 1980 525.97737 1981 480.84106 1982 456.38093 1983 437.04154 1984 461.65643 1985 462.93009 1986 473.03842 1987 491.57043 1988 491.20802 1989 533.36469 1990 541.8074 1991 560.47882 1992 705.48703 1993 701.86746 1994 674.41362 1995 671.48781 1996 658.257 1997 651.0535 1998 632.76426 1999 683.02213 2000 732.04069 2001 723.26723 2002 748.47633 2003 791.1248 2004 923.56601 2005 910.04607 2006 970.73706 2007 1031.80776 2008 1035.29692 2009 1016.18466 2010 1022.18059 2011 1011.85095 2012 1016.80575 2013 1029.01049 2014 1031.1415