Year	current US$
1997	3185931036.674555
1998	3416535491.444105
1999	3563295292.887001
2000	2546886544.9714923
2001	3181177308.387127
2002	3432496670.365751
2003	3706870421.601565
2004	4323237264.805821
2005	5155748515.628099
2006	5881459569.590683
2007	8204741983.406453
2008	9507414749.500935
2009	9675886297.65837
2010	10715433057.925789
2011	11702260644.305983
2012	13233225046.141445
2013	14150528913.742754
2014	15267753206.183899
2015	14884321870.475317
2016	16057706734.335201
2017	18096161335.860477
2018	17270492333.84898
2019	19266611570.159992