Year Measure 1971 458.72789 1972 497.62542 1973 552.87224 1974 602.88742 1975 649.09987 1976 719.3157 1977 787.12394 1978 856.90429 1979 938.00521 1980 1012.74548 1981 1017.75438 1982 1052.21562 1983 1108.04149 1984 1204.82813 1985 1279.25087 1986 1350.68393 1987 1364.41028 1988 1415.94317 1989 1446.33673 1990 1457.34767 1991 1483.01142 1992 1491.11427 1993 1534.81756 1994 1564.08884 1995 1631.61139 1996 1684.03027 1997 1758.875 1998 1804.24778 1999 1827.70539 2000 1891.97082 2001 1742.4857 2002 1800.51713 2003 1875.32316 2004 1948.4086 2005 2007.27743 2006 2063.09732 2007 2157.43734 2008 2218.88359 2009 2185.74526 2010 2361.05594 2011 2416.46285 2012 2485.58814 2013 2551.40799 2014 2601.36551