Year	current US$
2003	0.34851133
2004	0.42905232
2005	1.03720299
2006	2.61688413
2007	2.27911145
2008	2.12952078
2009	3.0403572
2010	2.30834125
2011	6.61799346
2012	3.39719244
2013	5.12832384
2014	3.44083464
2015	1.98502159
2016	1.83745885
2017	3.82756054
2018	2.27607537
2019	2.3239037
2020	1.61010058
2021	2.24633221