Year	US Dollars
1990	66960645309.0569
1991	73439467298.25632
1992	81719570671.8889
1993	91293139029.21779
1994	105788669183.16197
1995	116269318417.683
1996	125488831213.16701
1997	141944708592.39801
1998	139627596531.04999
1999	149897174292.91299
2000	164067142952.92996
2001	165482331133.948
2002	171998500849.802
2003	181950322059.58401
2004	197221055241.79001
2005	219823845542.62097
2006	254738302729.83102
2007	286518916034.65198
2008	293198198054.77698
2009	293262006413.84692
2010	356665493237.22705
2011	379732620005.95697
2012	395950522098.93304
2013	424074999876.52893
2014	455033916350.46301
2015	463603061831.24091
2016	473821775267.43103
2017	508278248025.09613