Year US Dollars adjusted for inflation) 1960 18142.87588 1961 19083.55897 1962 19786.85153 1963 20723.93784 1964 21972.8347 1965 22598.66626 1966 22852.67116 1967 23441.23789 1968 24157.94022 1969 25190.51956 1970 26464.33574 1971 26531.14094 1972 27058.29384 1973 28083.51421 1974 28897.70718 1975 29517.92516 1976 29721.96431 1977 29143.83431 1978 29568.09094 1979 30636.57753 1980 31094.20624 1981 31198.19672 1982 31569.69716 1983 32155.16194 1984 33484.73457 1985 34151.67484 1986 34989.33778 1987 36042.3586 1988 36795.19717 1989 37520.86883 1990 37513.0798 1991 36831.27389 1992 36191.65081 1993 35238.79397 1994 36419.45857 1995 37686.82527 1996 38198.01955 1997 39283.44555 1998 40921.15246 1999 42741.62286 2000 44693.7366 2001 45270.78107 2002 46059.36679 2003 46983.07726 2004 48820.60609 2005 49996.17522 2006 52046.48151 2007 53421.02024 2008 52711.19827 2009 49554.34343 2010 52076.25591 2011 53061.56857 2012 52519.68044 2013 52722.9123 2014 53561.89212 2015 55395.05871 2016 56473.02278 2017 56935.18827