Year	US Dollars
1990	16737452306.53
1991	21248651603.48429
1992	21868574858.0364
1993	23682999657.5702
1994	26178506939.29729
1995	28689583865.574
1996	30335426325.94571
1997	29886647098.77209
1998	30938520715.5535
1999	31376226792.72449
2000	32734818185.03189
2001	33998838063.0184
2002	34220738372.06829
2003	31501214894.3079
2004	39851088023.42741
2005	43563880748.7854
2006	46435246522.4006
2007	53349520060.9254
2008	58503987804.0713
2009	63521868497.6281
2010	68984197434.0206
2011	71578255977.8085
2012	75035589998.94832
2013	78264528610.75291
2014	80644338368.1492
2015	82183544196.8633
2016	84417020639.78868
2017	89346985479.44348