Year current US$ 1971 0 1972 0 1973 0 1974 0 1975 0 1976 0 1977 0 1978 0 1979 0 1980 0 1981 0 1982 0 1983 0 1984 0 1985 0 1986 0 1987 0 1988 0 1989 0 1990 0 1991 0 1992 0 1993 0 1994 0 1995 0 1996 0 1997 0 1998 0 1999 0 2000 0 2001 0 2002 0 2003 0 2004 0 2005 0 2006 0 2007 0 2008 0 2009 0 2010 1242261.11009299 2011 14030328.21168 2012 2219931.68592842 2013 5860462.76289457 2014 37831212.0097974 2015 501086.571028347 2016 402163.179475087 2017 787500.780762588 2018 1143986.3245139 2019 804303.121961452 2020 304637.643438715 2021 954520.825792162