Year	current US$
1987	500000000
1988	600000000
1989	600000000
1990	700000000
1991	650000000
1993	342857142.85714287
1994	217327459.61820853
1995	296194772.80947214
1996	184990791.89686927
1997	437798919.06674945
1998	497119684.8223961
1999	378795747.2234883
2000	537777028.856993
2001	518622874.8962019
2002	576493371.8056768
2003	837173733.674106
2004	951829550.7179251
2005	1186932849.3647912
2006	1203233256.3510392
2007	1247185741.08818
2008	1354888975.4577327
2009	1504210526.3157895
2010	1609824561.4035087
2011	1938596491.22807
2012	2089122807.0175438
2013	2376491228.070175
2014	2865614035.0877194
2015	3030285714.285714
2016	3109428571.428571
2017	3553714285.714286
2018	4086285714.285714
2019	4388571428.571428
2020	4591142857.142858
2021	5084285714.285714
2022	5549142857.142858