Year	US Dollars
1990	54987861988.9289
1991	56163563659.2982
1992	51929231090.50169
1993	49174112559.3588
1994	44215165104.5121
1995	40372301728.6892
1996	42327066470.16479
1997	47771871757.72849
1998	52340584222.5526
1999	55094458936.6912
2000	59604001770.5209
2001	63814442373.75261
2002	68210196571.89959
2003	74721604377.11098
2004	85540760042.45218
2005	96663593278.34409
2006	109056133705.03699
2007	120858467410.49701
2008	135265357648.37202
2009	135228151735.90703
2010	148072213975.86203
2011	159291474012.51801
2012	164707842139.67801
2013	166815020813.35098
2014	173616428281.53
2015	166522537640.44699
2016	163930664121.57596
2017	172433365597.991