Year Measure 1960 2698.7923 1961 2742.12347 1962 2887.23625 1963 3080.41407 1964 3273.50896 1965 3437.54077 1966 3636.64386 1967 3630.19414 1968 4000.82328 1969 4303.22392 1970 4681.29984 1971 4450.38251 1972 4527.21372 1973 4773.8114 1974 4510.44301 1975 4764.49901 1976 5151.25137 1977 5054.83376 1978 5016.74042 1979 5229.61827 1980 4871.53324 1981 5097.15446 1982 4877.7999 1983 4941.26701 1984 5216.25782 1985 5656.1929 1986 5878.80147 1987 5763.07044 1988 5854.49966 1989 5594.55297 1990 5514.55753 1991 5650.54138 1992 5369.37036 1993 5334.1665 1994 5660.27142 1995 5702.16504 1996 5825.09791 1997 5672.00818 1998 5769.69506 1999 5661.49146 2000 5360.14515 2001 5680.28049 2002 5802.11011 2003 5650.43805 2004 5847.34416 2005 5711.12728 2006 5529.07795 2007 5472.13539 2008 5379.9591 2009 4883.20049 2010 5427.92505 2011 5274.64361 2012 5269.486 2013 5146.53359 2014 4966.43592 2015 5102.78558