Year	current US$
2000	3.62494935
2001	4.0679316
2002	3.74311497
2003	4.03303625
2004	4.5230905
2005	6.25764937
2006	5.23940755
2007	5.95518208
2008	7.13898094
2009	6.97239888
2010	6.15116947
2011	7.72458524
2012	8.42003869
2013	10.20762725
2014	11.84389219
2015	10.78832387
2016	7.50873521
2017	8.06376819
2018	9.11716322
2019	9.35331264
2020	10.88270788
2021	12.64243672