Year current US$ 1970 0 1971 0 1972 0 1973 0 1974 0 1975 0 1976 0 1977 0 1978 0 1979 0 1980 486964.689812622 1981 589018.7054161 1982 1148484.91911083 1983 0 1984 42413.6317976275 1985 1461766.1880227 1986 1925088.24301781 1987 3160082.10062784 1988 3132740.50759305 1989 3627725.46799527 1990 6040774.0271281 1991 4431851.97590112 1992 1301102.04187815 1993 136847.140716586 1994 999046.195745018 1995 0 1996 3159967.22839275 1997 3595515.54413067 1998 3566202.593165 1999 3499458.90844124 2000 3295751.26564304 2001 4768701.38684602 2002 4089714.57023876 2003 5908868.87569943 2004 7331546.59163792 2005 9209118.65719949 2006 10442322.5547424 2007 8583678.71248228 2008 5831401.97617099 2009 1834588.45870346 2010 0 2011 0 2012 0 2013 0 2014 0 2015 0 2016 718402.819534475 2017 3598998.42013139 2018 5349301.55486859 2019 6781947.21828507 2020 10784932.835217 2021 8779779.86639752