Year	current US$
2003	2.75925182
2004	3.11439724
2005	2.38690368
2006	2.60879373
2007	3.17745556
2008	1.346271
2009	1.75832694
2010	4.89043876
2011	5.03122126
2012	4.19932375
2013	4.24587214
2014	3.40640691
2015	1.99714944
2016	2.11403882
2017	0.99088498
2018	4.22375912
2019	10.51444326
2020	5.13109319
2021	1.29893253