Year Measure 1971 464.93316 1972 477.16871 1973 483.71738 1974 486.16799 1975 527.48834 1976 537.17473 1977 577.21101 1978 617.1549 1979 619.04366 1980 609.4552 1981 597.14671 1982 606.83044 1983 621.91072 1984 651.07496 1985 657.75974 1986 671.2095 1987 694.42236 1988 720.3415 1989 724.11611 1990 766.99533 1991 736.8518 1992 752.62866 1993 788.12872 1994 816.16289 1995 866.83437 1996 881.65374 1997 871.75632 1998 869.35861 1999 878.52454 2000 898.98731 2001 928.81143 2002 984.81071 2003 1118.43177 2004 1268.1329 2005 1393.69132 2006 1515.17368 2007 1630.17103 2008 1672.90412 2009 1778.43352 2010 1954.72256 2011 2086.4869 2012 2155.16479 2013 2213.75933 2014 2236.72991