Year	current US$
2000	2.42460348
2001	2.19417164
2002	2.09164654
2003	2.96129552
2004	4.30574451
2005	5.97362262
2006	3.88747643
2007	4.19688045
2008	4.71907185
2009	5.0154832
2010	5.32475283
2011	5.57421807
2012	5.82296209
2013	5.87295293
2014	6.11441363
2015	5.94491948
2016	5.76090168
2017	5.71347524
2018	6.11618743
2019	6.19746619
2020	5.9480657
2021	6.10220892