Year	current US$
1971	0
1972	0
1973	0
1974	0
1975	0
1976	0
1977	0
1978	0
1979	0
1980	0
1981	5947688.64785155
1982	1843854.35545168
1983	6362756.66709658
1984	13722419.5283581
1985	16142250.4924966
1986	5987421.77289482
1987	11873828.054889
1988	8060661.12635654
1989	9699870.48865149
1990	12274118.8978377
1991	6313528.18434574
1992	20564530.6138874
1993	19530342.3684724
1994	15957565.534116
1995	7893650.31232443
1996	5056988.65721626
1997	3256458.62850641
1998	1834158.12495963
1999	0
2000	0
2001	0
2002	0
2003	0
2004	0
2005	0
2006	0
2007	0
2008	0
2009	0
2010	0
2011	0
2012	0
2013	0
2014	0
2015	4119196.6874421
2016	4261294.34460284
2017	7775073.41601382
2018	11481706.3245805
2019	9688284.72153879
2020	4646991.21535146
2021	0