Year US Dollars adjusted for inflation) 1960 5605.19172 1961 5815.23356 1962 5675.06004 1963 5290.76622 1964 5738.59769 1965 6251.32182 1966 6120.71218 1967 6226.99776 1968 6434.95378 1969 6954.76412 1970 7056.84806 1971 7335.75914 1972 7329.92116 1973 7407.36675 1974 7685.85721 1975 7559.14375 1976 7291.84043 1977 7681.01757 1978 7227.56412 1979 7849.36334 1980 8052.68965 1981 7478.13043 1982 6996.96292 1983 7154.41125 1984 7198.71994 1985 6550.15032 1986 6958.75247 1987 7053.98564 1988 6772.22302 1989 6173.68498 1990 5939.75692 1991 6598.72263 1992 7285.42943 1993 7612.68115 1994 7952.71155 1995 7630.02227 1996 7955.12765 1997 8500.94036 1998 8728.94765 1999 8339.89439 2000 8182.6865 2001 7735.49336 2002 6816.73486 2003 7337.79204 2004 7913.74312 2005 8522.52273 2006 9112.11316 2007 9830.68092 2008 10125.12627 2009 9428.50254 2010 10276.2605 2011 10780.01566 2012 10557.88539 2013 10699.19772 2014 10323.20694 2015 10498.59253 2016 10206.24955 2017 10398.09246