Year	current US$
2000	1.95220104
2001	2.47750003
2002	2.86783074
2003	2.9119962
2004	4.67887585
2005	6.02599039
2006	6.80959555
2007	6.60671577
2008	6.91904871
2009	7.4235246
2010	6.84908619
2011	8.92457331
2012	7.03881735
2013	17.35833247
2014	12.24396848
2015	19.38259419
2016	8.24546506
2017	8.86000511
2018	8.08707675
2019	7.99347357
2020	7.9885953
2021	8.89259336