Year Measure 1971 612.58374 1972 598.97529 1973 589.07156 1974 610.11274 1975 623.48204 1976 633.80957 1977 638.02536 1978 621.08497 1979 592.80041 1980 638.33318 1981 632.04076 1982 635.43281 1983 641.6209 1984 648.68469 1985 644.58516 1986 687.1891 1987 696.06641 1988 702.9328 1989 694.9587 1990 706.78433 1991 701.289 1992 704.35482 1993 723.83844 1994 736.60572 1995 737.1056 1996 743.03374 1997 709.82167 1998 732.19548 1999 645.17449 2000 638.88582 2001 627.17942 2002 606.26675 2003 610.4943 2004 608.5252 2005 625.69745 2006 649.37619 2007 637.51184 2008 659.61195 2009 676.04427 2010 679.53043 2011 673.43141 2012 672.86825 2013 710.85777 2014 711.58318