Year Measure 1971 394.40075 1972 412.93373 1973 416.74603 1974 433.3627 1975 441.82688 1976 449.68315 1977 477.66924 1978 470.79989 1979 480.77511 1980 502.84807 1981 529.3789 1982 553.77754 1983 518.26219 1984 554.40998 1985 547.09768 1986 569.60672 1987 594.08235 1988 556.5786 1989 553.70294 1990 546.35025 1991 578.95821 1992 475.91913 1993 522.38099 1994 533.46078 1995 546.36762 1996 588.72208 1997 606.74885 1998 642.14928 1999 655.13102 2000 680.1884 2001 706.05627 2002 740.8238 2003 764.98628 2004 802.83959 2005 837.29289 2006 887.62253 2007 968.12877 2008 1039.45328 2009 1040.63558 2010 1094.31427 2011 1241.66713 2012 1211.31474 2013 1267.59668 2014 1307.51097