Year	current US$
1990	53461903.46119
1991	50864408.8032082
1992	44181355.5112637
1993	41215620.1524814
1994	38710226.3416551
1995	41991145.0759103
1996	36323941.4968697
1997	38634217.2066242
1998	32225937.7818501
1999	28260408.3545218
2000	30197561.7799134
2001	29712128.99221
2002	27771093.3862076
2003	27105494.532704
2004	31123446.3052269
2005	39269324.7601117
2006	43171343.3267965
2007	42690793.5198882
2008	46056986.9848647
2009	45900882.3118017
2010	47223435.1105781
2011	49657160.1414615
2012	50254838.6704893
2013	51122399.1724962
2014	54253918.4501583
2015	63532274.2614356
2016	53026561.7157195
2017	53979687.0042463
2018	53435981.88464
2019	50212750.3508571
2020	50868139.4609602
2021	51736746.8322612