Year	constant 2015 US$
1999	5234.179365415501
2000	5005.967616625444
2001	5451.534281241332
2002	5275.560445966025
2003	5601.822195836913
2004	5368.22777091013
2005	5747.654593549405
2006	6455.183120053315
2007	7250.49639896536
2008	7404.427749856973
2009	9876.51509641555
2010	11351.627203287077
2011	13586.740943957142
2012	14797.89353725721
2013	15670.994076875968
2014	18706.83285326782
2015	21499.9031718683
2016	21964.95391972673
2017	17833.618554897133
2018	18334.525888386073
2019	19120.217370681414
2020	20470.335742468797
2021	19404.736768881172
2022	19411.190120500465