Year Measure 1960 4049.78663 1961 4182.1755 1962 4433.60602 1963 4690.48626 1964 4970.44646 1965 5234.685 1966 5590.33374 1967 5888.34092 1968 6385.45933 1969 6904.8338 1970 7236.65704 1971 7517.30465 1972 8076.40927 1973 8573.19415 1974 8449.92846 1975 8522.394 1976 8968.77566 1977 9337.72402 1978 9560.54541 1979 9700.69539 1980 9862.3655 1981 9976.69371 1982 9544.46094 1983 9742.00571 1984 10282.37464 1985 10414.2079 1986 10424.4273 1987 10886.85826 1988 11298.33251 1989 11531.93231 1990 11713.3317 1991 12134.17213 1992 12014.95825 1993 12261.52378 1994 12455.16217 1995 12659.60763 1996 12854.29891 1997 12889.83228 1998 13154.76303 1999 13281.86998 2000 13671.05202 2001 13046.61415 2002 13296.1823 2003 13307.49201 2004 13388.58971 2005 13704.57705 2006 13583.26696 2007 13657.45283 2008 13663.42797 2009 12913.71469 2010 13394.4144 2011 13243.29778 2012 12959.41462 2013 12996.84549 2014 12984.33311