Year US Dollars adjusted for inflation) 1961 3380.63534 1962 3703.48082 1963 4142.29188 1964 4392.21146 1965 4904.75224 1966 4948.77763 1967 4902.65138 1968 4962.70107 1969 5438.13812 1970 5796.16866 1971 6086.20191 1972 6604.23218 1973 7208.91977 1974 7153.32949 1975 7053.51046 1976 8091.35714 1977 8910.54323 1978 9473.42707 1979 10006.13359 1980 10727.28234 1981 11448.69782 1982 11604.83525 1983 12113.00653 1984 13190.82432 1985 13148.67802 1986 14421.62642 1987 16190.08563 1988 17421.0952 1989 17634.15771 1990 18250.90083 1991 19132.2528 1992 20155.19092 1993 21040.4988 1994 21813.70375 1995 21893.6705 1996 21835.03458 1997 22758.30153 1998 21241.43755 1999 21566.91811 2000 23015.88824 2001 22975.03477 2002 23252.44675 2003 24010.46658 2004 25896.62106 2005 27688.69844 2006 29446.23689 2007 31081.54801 2008 31553.61323 2009 30711.48476 2010 32549.99823 2011 33888.49592 2012 34086.32123 2013 35002.51749 2014 35717.67916 2015 36260.59546 2016 36816.14986 2017 37927.13462