Year Measure 1971 176.23272 1972 201.61347 1973 182.29997 1974 210.75967 1975 236.47394 1976 229.77263 1977 223.5552 1978 288.61317 1979 316.26455 1980 356.52005 1981 414.03455 1982 520.84273 1983 600.47207 1984 589.52406 1985 618.20147 1986 606.49173 1987 590.5367 1988 628.03613 1989 677.04465 1990 688.80622 1991 700.57328 1992 702.35386 1993 687.32566 1994 751.48586 1995 832.38693 1996 893.10366 1997 914.05305 1998 958.1335 1999 1012.91876 2000 1064.90536 2001 1144.1591 2002 1233.32877 2003 1294.20934 2004 1399.19731 2005 1503.33888 2006 1549.61859 2007 1559.58348 2008 1584.9593 2009 1543.00913 2010 1853.43297 2011 1690.23255 2012 1365.13433 2013 1056.43147 2014 949.58676