Year	current US$
2000	9.91217993
2001	9.17377584
2002	10.09079053
2003	11.80631046
2004	12.41112602
2005	14.04065973
2006	15.69315631
2007	18.66713943
2008	21.56082214
2009	21.99843849
2010	18.12024121
2011	16.26460744
2012	12.6484042
2013	10.75876925
2014	12.30646852
2015	10.16476564
2016	10.11930624
2017	10.96379742
2018	10.40525896
2019	9.99943556
2020	12.9079601
2021	13.67855071