Year	current US$
2000	2.5217620268300966
2001	2.005973897245521
2002	2.2760076826901314
2003	3.726222311354271
2004	4.9555773951355215
2005	7.568832538518474
2006	7.658055914627895
2007	8.572017706074465
2008	9.70343875152487
2009	10.389591440267065
2010	11.623180442927033
2011	12.819784138341932
2012	12.42683317740599
2013	13.821069056868065
2014	11.902855508755302
2015	10.4053104144699
2016	9.74081219012803
2017	9.681596711199244
2018	10.00001238426147
2019	10.678623607403717
2020	9.96133529341058
2021	11.382889640174355