Year Measure 1971 677.88586 1972 1307.24847 1973 1689.43586 1974 1860.55787 1975 2296.49086 1976 2790.04487 1977 3673.22224 1978 4107.8917 1979 4875.84555 1980 5626.52535 1981 5986.26104 1982 6969.05119 1983 7526.37543 1984 7758.9463 1985 8023.424 1986 8094.58925 1987 8137.92114 1988 8334.69719 1989 8090.34858 1990 8355.66995 1991 8015.12264 1992 8150.42755 1993 8958.0299 1994 9275.61724 1995 9273.44599 1996 9394.71494 1997 9820.334 1998 11133.68063 1999 12128.52583 2000 12232.62043 2001 12048.59123 2002 12401.23265 2003 12266.92521 2004 11902.35354 2005 12303.14165 2006 11823.08693 2007 11688.32179 2008 11613.97901 2009 10966.43493 2010 10968.25849 2011 10612.4261 2012 10698.21952 2013 10952.71146 2014 11263.53192