Year Measure 1960 1906.17493 1961 1937.64474 1962 2052.05448 1963 2182.99311 1964 2320.01313 1965 2539.59773 1966 2710.0782 1967 2815.68799 1968 3052.89657 1969 3193.65508 1970 3417.67466 1971 3414.31664 1972 3503.42995 1973 3608.10122 1974 3580.59955 1975 3651.68081 1976 3962.23292 1977 4060.10628 1978 4360.47071 1979 4467.19363 1980 4491.90698 1981 4414.96406 1982 4262.39171 1983 4427.79292 1984 4672.13755 1985 4815.3139 1986 5024.07619 1987 5048.49931 1988 4817.15567 1989 4984.19812 1990 4966.89358 1991 5105.1082 1992 5159.64862 1993 5459.62341 1994 5315.24487 1995 5391.41408 1996 5202.04728 1997 5475.18874 1998 5684.78859 1999 5913.30221 2000 5826.07777 2001 5954.04177 2002 5501.11774 2003 5933.21584 2004 5769.32671 2005 5802.71629 2006 5833.77393 2007 5862.21726 2008 6752.70898 2009 6484.11859 2010 6934.5902 2011 5649.69772 2012 5906.14105 2013 6415.99071 2014 5595.65462 2015 5815.80733