Year	current US$
2000	2.5940475
2001	2.16258722
2002	2.64794626
2003	2.36652825
2004	2.22064723
2005	2.27796886
2006	2.30655639
2007	2.32017981
2008	2.54728649
2009	2.27643254
2010	1.86165681
2011	2.03484671
2012	1.94592126
2013	3.30095549
2014	4.49132942
2015	4.49469159
2016	3.3108259
2017	3.50791427
2018	3.87554456
2019	3.84804448
2020	3.46788157
2021	3.95233303