Year current US$ 1970 3414.622293799428 1971 3758.307737787524 1972 4257.451046059896 1973 4839.689667577622 1974 5712.946183043787 1975 6148.6250438164 1976 7231.924597487366 1977 7288.63141217861 1978 7439.3067452061805 1979 7922.762840930851 1980 8745.604821132707 1981 9752.938458491377 1982 9873.077907017463 1983 10706.57485071601 1984 11097.109824050389 1985 11332.258972115442 1986 11704.987163297112 1987 13252.829639080728 1988 15354.49804778871 1989 16740.828939883337 1990 17207.343172986282 1991 17586.4766020718 1992 16735.09110173121 1993 16170.209939432167 1994 16017.944157000376 1995 16619.92657840728 1996 17002.699841705322 1997 17542.888960405468 1998 16794.229268229104 1999 17868.200033476478 2000 19386.4454096933 2001 18986.18294037482 2002 19537.081005584998 2003 22686.55397254335 2004 26003.164647179525 2005 29229.897191355405 2006 33132.78863069891 2007 36533.917459509576 2008 37787.147044501486 2009 32986.04810497861 2010 38678.18058655671 2011 42617.974060283435 2012 43024.450803671316 2013 43054.54264518803 2014 41608.03614682041 2015 35364.11910717832 2016 34318.54492371687 2017 36906.31171710907 2018 37828.316857249636 2019 37785.727608927205 2020 34953.036361061364 2021 41986.23285958836