Year	current US$
1970	1438835.87836712
1971	1521872.69450566
1972	1877694.73314747
1973	5196620.74239367
1974	7142500.4065521
1975	4410987.99982071
1976	4164795.11999838
1977	4152821.76752386
1978	2590013.38984375
1979	3284991.17566136
1980	4459935.36999141
1981	4078124.46774085
1982	6283929.5113452
1983	5017290.46080463
1984	5670572.93778494
1985	4872913.47770595
1986	3056926.90860433
1987	2475911.9297871
1988	9209897.93669517
1989	10618946.8238795
1990	5374638.29004389
1991	2806219.94893809
1992	3400717.87531186
1993	2088520.36272161
1994	4231408.46326498
1995	2567470.09083072
1996	3717288.50022714
1997	1536872.48313192
1998	3025210.60894496
1999	1786084.94417122
2000	1649387.21009281
2001	1390372.97538682
2002	1021767.59192847
2003	689354.716873295
2004	3510207.55983018
2005	9293390.17075188
2006	14978570.046209
2007	18520529.0896492
2008	35671050.2483884
2009	17576045.8996862
2010	26023305.8428847
2011	29405618.0590323
2012	29861066.1266842
2013	17496417.3261879
2014	8810257.37535465
2015	4832687.64791054
2016	4694946.45034277
2017	5773689.34541421
2018	4424827.40530785
2019	3967854.54036945
2020	2152074.35087107
2021	4758682.84984816