Year	US Dollars
1990	24849717235.3469
1991	20259029237.1652
1992	11340662405.475
1993	8124445476.39378
1994	7427703421.06489
1995	7568971060.51088
1996	8762385630.72812
1997	10447534658.2705
1998	11064676155.2483
1999	11543489077.8627
2000	11868840467.3898
2001	12376148980.8334
2002	13166665748.2108
2003	14913670503.3238
2004	16415424940.4446
2005	18465736166.3769
2006	21053794717.4977
2007	23867225649.8166
2008	24474374496.8029
2009	23821302333.9946
2010	25102132868.86621
2011	27516606244.2349
2012	30417818963.69469
2013	31645188373.4897
2014	34034953901.033
2015	34743833777.7532
2016	35364389429.2282
2017	37635077520.1878