Year Measure 1960 1952.58863 1961 1994.32463 1962 2124.84854 1963 2281.28993 1964 2341.14631 1965 2378.33973 1966 2387.68488 1967 2388.41235 1968 2561.52258 1969 2772.01093 1970 3860.86494 1971 3895.26473 1972 4017.33739 1973 4240.06186 1974 4158.27163 1975 3984.97424 1976 4314.58164 1977 4336.0874 1978 4483.88085 1979 4685.29673 1980 4562.29597 1981 4399.49982 1982 4257.86441 1983 4268.04891 1984 4447.31664 1985 4598.13849 1986 4589.15366 1987 4616.39706 1988 4629.17767 1989 4514.70471 1990 4421.36453 1991 4302.89118 1992 4190.98422 1993 4122.69574 1994 4088.79813 1995 4119.68895 1996 4246.55319 1997 4203.35737 1998 4177.29413 1999 4079.93334 2000 4094.06036 2001 4209.79609 2002 4108.4013 2003 4084.50335 2004 4114.38993 2005 4086.50341 2006 4204.65469 2007 3985.81195 2008 4036.83078 2009 3790.50115 2010 3997.07942 2011 3869.81623 2012 3876.9481 2013 3939.52956 2014 3779.46192 2015 3817.54941