Year Measure 1971 1380.9214 1972 1379.81892 1973 1411.49678 1974 1415.68295 1975 1378.54699 1976 1404.74478 1977 1420.56776 1978 1426.91926 1979 1484.56582 1980 1487.61708 1981 1430.44008 1982 1416.54002 1983 1419.93017 1984 1447.81983 1985 1360.66541 1986 1421.54698 1987 1477.04343 1988 1504.81909 1989 1441.48227 1990 1407.38675 1991 1430.51498 1992 1483.77944 1993 1468.22078 1994 1541.65752 1995 1544.35577 1996 1582.1382 1997 1613.91899 1998 1650.34373 1999 1659.99283 2000 1661.11704 2001 1562.68636 2002 1502.03719 2003 1589.54508 2004 1717.65052 2005 1709.57235 2006 1840.44044 2007 1845.09812 2008 1923.13981 2009 1850.86153 2010 1908.28056 2011 1933.52303 2012 1920.08096 2013 1951.43945 2014 2015.18704