Year Measure 1971 714.03848 1972 746.88214 1973 799.1386 1974 830.31705 1975 846.44899 1976 867.52878 1977 875.46642 1978 909.71734 1979 944.67698 1980 939.67784 1981 880.59902 1982 874.75834 1983 876.31719 1984 912.20964 1985 953.39774 1986 977.65227 1987 995.69936 1988 990.0155 1989 991.4412 1990 938.76755 1991 940.00137 1992 933.90059 1993 941.62446 1994 975.31576 1995 992.59454 1996 1028.80175 1997 1064.04804 1998 1072.76407 1999 1080.6411 2000 1069.33747 2001 1072.91729 2002 1086.6367 2003 1090.38898 2004 1136.96824 2005 1152.01634 2006 1178.85091 2007 1232.60168 2008 1288.11729 2009 1233.75363 2010 1351.0289 2011 1359.12236 2012 1404.75527 2013 1451.1678 2014 1484.92664