Year	current US$
2000	2.01005205
2001	1.78576216
2002	1.98713171
2003	2.41295453
2004	5.60061979
2005	6.62936611
2006	6.24643202
2007	7.76602739
2008	7.3312915
2009	9.37793256
2010	6.43808442
2011	12.54529529
2012	18.89673962
2013	14.34535413
2014	12.98964749
2015	10.90952113
2016	2.79597384
2017	3.81695468
2018	2.61036187
2019	4.12936195
2020	8.88620932
2021	5.47421558