Year	current US$
2000	6.96425152
2001	8.52990627
2002	9.95218277
2003	11.15465164
2004	14.22916508
2005	18.49229622
2006	18.09505653
2007	19.3034668
2008	24.26328468
2009	27.63411713
2010	26.17583847
2011	30.28253746
2012	35.03115845
2013	41.17826843
2014	43.08488846
2015	39.91206741
2016	31.38208961
2017	36.26471329
2018	40.8117218
2019	40.41284943
2020	34.37060928
2021	44.52215576