Year US Dollars adjusted for inflation) 1960 2980.5765 1961 3237.90789 1962 3425.98883 1963 3580.69341 1964 3808.94361 1965 4348.99402 1966 4711.41238 1967 5120.90101 1968 5723.74583 1969 6483.03429 1970 7014.93821 1971 7816.18698 1972 8707.10144 1973 9198.8522 1974 9524.88796 1975 9026.08363 1976 10265.70022 1977 9544.85786 1978 7938.61912 1979 6859.86105 1980 4789.58418 1981 4366.70269 1982 5333.98173 1983 5556.96 1984 4864.83493 1985 4773.45427 1986 4119.69823 1987 3989.24536 1988 3640.43115 1989 3739.72885 1990 4147.36065 1991 4567.57197 1992 4625.68803 1993 4615.92013 1994 4490.28305 1995 4528.29554 1996 4684.64588 1997 4622.59719 1998 4635.30393 1999 4591.46152 2000 4781.85082 2001 4749.80631 2002 5028.43736 2003 5401.7502 2004 5572.90572 2005 5684.9575 2006 5901.64179 2007 6311.7895 2008 6256.87797 2009 6247.69166 2010 6531.92743 2011 6622.67294 2012 6052.51683 2013 5964.17905 2014 6161.10352 2015 6007.00489 2016 6733.9125 2017 6946.85658