Year US Dollars adjusted for inflation) 1960 6779.88678 1961 7476.29746 1962 7545.85722 1963 8279.94281 1964 8931.28391 1965 9724.5722 1966 10241.81496 1967 10715.5883 1968 11355.57426 1969 12434.22511 1970 13392.30814 1971 14379.90075 1972 15738.28247 1973 16934.80245 1974 15786.26958 1975 16634.47483 1976 17500.31292 1977 17782.12085 1978 18825.09062 1979 19202.05508 1980 19143.12411 1981 18677.47507 1982 18352.43986 1983 18049.18374 1984 18320.5842 1985 18707.56898 1986 18742.31606 1987 18257.80403 1988 18971.64351 1989 19590.06779 1990 19383.93465 1991 19746.38214 1992 19733.29041 1993 19303.66698 1994 19591.39952 1995 19909.5296 1996 20389.31802 1997 21198.79065 1998 21902.73878 1999 22489.31596 2000 23275.44431 2001 24111.41745 2002 24965.59403 2003 26349.27734 2004 27614.40593 2005 27698.51061 2006 29176.39287 2007 30054.88939 2008 29874.74345 2009 28514.81009 2010 26917.75898 2011 24495.71113 2012 22830.52678 2013 22251.25729 2014 22565.68048 2015 22648.76988 2016 22687.60033 2017 23027.41345