Year	current US$
1987	700000000
1988	700000000
1989	800000000
1990	1000000000
1991	950000000
1992	348000000
1993	577777777.7777778
1994	837004405.2863436
1995	402413720.89924425
1996	300491098.8336403
1997	495804518.9229485
1998	655564947.6627928
1999	608761423.4411027
2000	654675406.7946765
2001	816463384.1466105
2002	934027755.5174953
2003	1142862892.6767423
2004	1255210745.715609
2005	1501814882.0326676
2006	1767369515.0115473
2007	2387804878.0487804
2008	2066225165.5629137
2009	2125614035.0877192
2010	2561052631.578947
2011	2597192982.45614
2012	2989473684.210526
2013	3321754385.9649124
2014	3610526315.7894735
2015	3331714285.714286
2016	3807714285.714286
2017	4216571428.571429
2018	4501142857.142858
2019	4890285714.285714
2020	5265428571.428572
2021	5904857142.857142
2022	6563714285.714286