Year	current US$
1997	3785264045.599861
1998	4556010240.164491
1999	5073233525.35139
2000	5061015409.609263
2001	5687285330.208521
2002	6183840349.664892
2003	6606471436.338098
2004	9144227004.566805
2005	10662801169.852367
2006	12047332881.581196
2007	15404681725.173655
2008	17617617791.555298
2009	17731747301.404404
2010	21911524412.554203
2011	19403983284.719162
2012	22364664025.43883
2013	24552900672.45071
2014	26791985091.880135
2015	25906385654.26974
2016	26758326392.247074
2017	28053764792.62812
2018	32347248555.226006
2019	35608230395.67275