Year	current US$
2008	4981698803.57195
2009	6962887411.55931
2010	11484655048.0814
2011	17505940564.6933
2012	17909536000.3817
2013	18994440504.0324
2014	20759321902.3414
2015	20646180102.0351
2016	20988233539.0769
2017	21854222107.2883