Year	current US$
1971	477935.474530905
1972	682381.05665757
1973	1224236.44948476
1974	2531598.71674565
1975	2659908.98912122
1976	2050777.34253466
1977	3673262.99636461
1978	3992294.88009436
1979	6534841.73664578
1980	5542746.6630376
1981	5981242.93457593
1982	3729987.16903455
1983	4500433.27300075
1984	4087411.92329497
1985	5270810.32447
1986	3521065.40682357
1987	2955944.31486746
1988	2832441.47622188
1989	1885702.61856381
1990	2577750.87300811
1991	1447505.82743978
1992	1123750.43053291
1993	1023167.05257002
1994	892804.873769449
1995	466271.583175953
1996	660503.31498388
1997	1787656.94017948
1998	1236571.25790113
1999	1564005.76691424
2000	2944402.49521153
2001	2357072.18308961
2002	2575560.81094989
2003	2312595.97186801
2004	3804895.89093135
2005	2860799.82169757
2006	5659264.78433753
2007	6878029.85238529
2008	6800753.92683446
2009	4177231.24148
2010	6469100.03911072
2011	9641397.81643011
2012	9179334.26851792
2013	11366764.0133539
2014	8819682.72170941
2015	4670574.677114
2016	3286806.59010107
2017	4013277.91986715
2018	6669937.06123759
2019	7009806.1636273
2020	6538168.00677979
2021	11226206.2557387