Year	US Dollars
1990	14972429564.6799
1991	15928335372.4624
1992	17821337960.9068
1993	19613136685.24
1994	21363226250.9046
1995	23130946878.6001
1996	23955601573.5383
1997	25363945399.119
1998	26558965548.4868
1999	27459405675.0846
2000	28753199102.9191
2001	29936077584.5785
2002	30910083205.9097
2003	32019436568.9557
2004	33599862145.3727
2005	36000164288.7347
2006	38801285499.3651
2007	41396486481.5339
2008	43660436873.2837
2009	42058522896.30659
2010	43073583472.7193
2011	44769511733.8159
2012	45253619011.1688
2013	46682248178.7154
2014	48490464200.99719
2015	50842515809.0154
2016	52423104122.11831
2017	48080091785.18471