Year Measure 1960 5641.74076 1961 5612.0795 1962 5774.58631 1963 5986.78395 1964 6136.93823 1965 6307.8902 1966 6591.34056 1967 6809.82048 1968 7073.47895 1969 7332.36855 1970 7569.0766 1971 7644.5248 1972 7940.99783 1973 8163.60379 1974 7909.58648 1975 7656.26358 1976 8100.56222 1977 8285.5709 1978 8438.40308 1979 8327.04171 1980 7942.25302 1981 7647.53805 1982 7259.0789 1983 7199.11853 1984 7443.32002 1985 7456.2629 1986 7376.09624 1987 7622.17302 1988 7849.75397 1989 7890.2872 1990 7671.77307 1991 7631.46781 1992 7677.4014 1993 7709.49659 1994 7757.83082 1995 7763.75511 1996 7844.46827 1997 7828.5811 1998 7803.6976 1999 7923.22389 2000 8056.86385 2001 7827.88633 2002 7843.34485 2003 7794.23553 2004 7881.57864 2005 7846.49969 2006 7697.65254 2007 7758.16599 2008 7488.08192 2009 7056.78365 2010 7161.16546 2011 7028.58312 2012 6869.49705 2013 6901.78682 2014 6955.52402 2015 6797.62061