Year	US Dollars
1990	7108279420.5618
1991	6808427541.37499
1992	6202838027.0886
1993	6057337229.8461
1994	6410470794.90871
1995	6979289298.91233
1996	7323206370.69824
1997	7742800269.43286
1998	8174149069.7184
1999	8551826508.58371
2000	8805377244.33371
2001	9299803552.32343
2002	9873256951.62886
2003	10732416090.3785
2004	12219622687.8185
2005	13324016370.8936
2006	15030598503.9741
2007	16830446129.1948
2008	18537899011.3567
2009	18216297086.4086
2010	18835306939.1683
2011	22505271782.4175
2012	25888698054.5577
2013	30031790142.8663
2014	32113783679.4347
2015	33208154416.74739
2016	34582776340.6832
2017	34369642551.3483