Year	current US$
2000	2.24894441
2001	1.90022796
2002	2.30828063
2003	2.92615027
2004	3.74384563
2005	3.08273263
2006	4.87722431
2007	4.73331115
2008	3.87688663
2009	6.28051624
2010	4.65781758
2011	6.20993934
2012	8.04545275
2013	5.21222126
2014	6.0475783
2015	3.91559267
2016	4.05331317
2017	2.87006756
2018	4.47069124
2019	2.41548742
2020	2.86541173
2021	7.94837413