Year US Dollars adjusted for inflation) 1960 3425.42997 1961 3668.48808 1962 3747.85989 1963 3671.29025 1964 3690.91512 1965 3697.50627 1966 3745.99592 1967 3825.23772 1968 4151.00984 1969 4438.58864 1970 4706.72119 1971 5109.59134 1972 5587.38992 1973 6216.91646 1974 6618.72001 1975 6798.95591 1976 7288.44015 1977 7444.83947 1978 7505.24448 1979 7825.85333 1980 8340.3231 1981 7789.3179 1982 7654.52688 1983 7226.45158 1984 7440.05103 1985 7861.00899 1986 8315.92982 1987 8446.10435 1988 8277.58858 1989 8392.25284 1990 7987.05522 1991 7967.80338 1992 7797.82726 1993 8028.20393 1994 8320.26047 1995 8549.02152 1996 8599.10165 1997 8751.37999 1998 8645.5134 1999 8555.91567 2000 8779.2908 2001 8777.35713 2002 8924.89696 2003 8911.31951 2004 9309.89206 2005 9495.48465 2006 9761.83428 2007 10244.26715 2008 10656.86947 2009 10538.77828 2010 11224.15408 2011 11560.41875 2012 11673.77054 2013 11915.41705 2014 11870.14841 2015 11351.56575 2016 10868.65344 2017 10888.98239