Year	current US$
2000	5.073046051041249
2001	5.225898974008497
2002	5.269399585110064
2003	5.840656159184425
2004	6.826534385038246
2005	7.877859657209979
2006	8.459953590895067
2007	9.56537345946735
2008	10.545700435788614
2009	10.589190361056636
2010	11.17761855300511
2011	11.859495964549108
2012	13.186182863292345
2013	13.694116682481958
2014	14.316553106620908
2015	14.226114125331346
2016	13.983420155207405
2017	14.40177397860545
2018	14.7603033593069
2019	15.13861818196058
2020	16.43465217950302
2021	17.15898186498775