Year current US$ 1970 1537790.86198491 1971 1220307.66466127 1972 1110341.73416451 1973 6558626.12210937 1974 9644954.17646769 1975 1724072.361138 1976 1846729.18429604 1977 1006054.45091233 1978 621381.678239184 1979 1712973.15748884 1980 766412.346578196 1981 464037.740750702 1982 939430.607183433 1983 355374.952623012 1984 25295.5231941203 1985 69386.4030034195 1986 0 1987 137729.878216572 1988 5834262.49888198 1989 8529709.82035687 1990 3207096.9058615 1991 1920815.90469564 1992 3956840.587979 1993 2354727.43352535 1994 1921139.89195412 1995 1242730.95648756 1996 1188343.98555948 1997 411491.58544574 1998 2565840.54413375 1999 1992536.12763474 2000 1558169.52670775 2001 1130309.11035488 2002 758026.710739408 2003 430926.154139343 2004 514963.190878445 2005 4234259.39881548 2006 7445436.85017004 2007 14520859.0585885 2008 18992003.2855178 2009 4480307.60889143 2010 18365339.6265942 2011 26963173.3004012 2012 22369022.5039774 2013 25687730.7457652 2014 14485287.5495306 2015 6208485.99495831 2016 8259695.49030838 2017 11415234.7283463 2018 0 2019 0 2020 0 2021 0