Year	current international $
2000	3.84362222627526
2001	4.10377586288205
2002	4.35988771062034
2003	4.4232072824654
2004	4.73363709029367
2005	5.17849315458091
2006	5.10143690519205
2007	5.55244324629809
2008	5.37777608867458
2009	5.32846187939507
2010	5.4861560286982
2011	5.52415505161668
2012	5.48681660571139
2013	6.03858172661393
2014	6.08156900055157
2015	6.20978501869794
2016	6.11250291065435
2017	6.80313972053251
2018	7.1429009352478
2019	7.88944571642851
2020	7.1732206505127
2021	7.34635877727205