Year Measure 1960 2412.1374 1961 2553.69318 1962 2780.65728 1963 3002.0876 1964 3127.46296 1965 3330.18388 1966 3425.80309 1967 3506.88706 1968 3762.59018 1969 4006.33097 1970 4166.9324 1971 4254.65241 1972 4372.63695 1973 4671.7183 1974 4534.25428 1975 4492.42163 1976 4587.68852 1977 4668.42317 1978 4729.84939 1979 4922.91573 1980 4683.93274 1981 4572.95385 1982 4480.33541 1983 4549.17529 1984 4597.73969 1985 4826.71453 1986 4953.65358 1987 5082.43981 1988 5232.73765 1989 5295.22453 1990 5356.57521 1991 5451.67717 1992 5452.39333 1993 5491.98912 1994 5380.26427 1995 5575.80849 1996 5815.8284 1997 5831.95755 1998 5908.87149 1999 6007.48442 2000 6114.52926 2001 6141.98255 2002 6142.74983 2003 6174.5509 2004 6138.75414 2005 6270.98406 2006 6200.55411 2007 6102.39677 2008 6015.72686 2009 5643.12859 2010 5700.85586 2011 5471.92413 2012 5449.2522 2013 5409.63039 2014 5129.52779