Year	current US$
2006	20786.29702008609
2007	23908.784993215806
2008	26298.848835747776
2009	24419.489744675193
2010	21641.90035841388
2011	20268.839913797234
2012	18108.18941495151
2013	17844.248416657556
2014	17998.023521528426
2015	15044.374439370613
2016	14903.30493358362
2017	15546.665997476819
2018	16496.93584452135
2019	16155.113668195236
2020	14754.743492081814
2021	17262.586536423973