Year US Dollars adjusted for inflation) 1960 5039.08757 1961 5634.32949 1962 5692.39473 1963 5926.93352 1964 6303.57932 1965 6283.71952 1966 6485.42857 1967 6574.96676 1968 6876.57524 1969 7016.29518 1970 7201.68056 1971 7197.67802 1972 7516.46866 1973 7533.26328 1974 7706.67925 1975 7708.95797 1976 8089.41923 1977 8707.58814 1978 9449.32368 1979 9651.31491 1980 9406.77021 1981 9649.97413 1982 9856.16462 1983 8699.41834 1984 8078.38086 1985 7644.68242 1986 7311.85068 1987 6912.95954 1988 6588.96144 1989 6487.45914 1990 6540.71427 1991 6672.41577 1992 6522.31003 1993 6391.76696 1994 6588.3958 1995 6869.49812 1996 7339.93225 1997 7877.61857 1998 8505.0654 1999 9171.36043 2000 9779.49634 2001 10151.96096 2002 10910.89782 2003 12426.14911 2004 13346.59238 2005 14105.34131 2006 15892.28724 2007 16570.06904 2008 17052.25938 2009 16226.51311 2010 16683.94578 2011 16551.48645 2012 16680.68044 2013 16761.08637 2014 16641.73767 2015 16824.67264 2016 15765.96432 2017 15350.85058