Year Measure 1971 297.20058 1972 301.35799 1973 307.07739 1974 310.3151 1975 314.62314 1976 320.82188 1977 347.86821 1978 363.45959 1979 371.45055 1980 377.67944 1981 388.28743 1982 388.83447 1983 387.09654 1984 393.51473 1985 398.9133 1986 431.18869 1987 436.66903 1988 440.18404 1989 456.70996 1990 543.70487 1991 560.51531 1992 574.48475 1993 620.71033 1994 611.7073 1995 664.35734 1996 678.27168 1997 691.00222 1998 666.39995 1999 688.38201 2000 735.82086 2001 742.69678 2002 759.64255 2003 751.30894 2004 789.92699 2005 792.92688 2006 800.53944 2007 785.99278 2008 790.78442 2009 843.45253 2010 874.58064 2011 831.55603 2012 851.73143 2013 863.04351 2014 883.91098