Year	current international $
2000	3.98203748376746
2001	3.99836392323465
2002	5.1436126556281
2003	4.53487696099803
2004	3.92374564090393
2005	3.99818694299674
2006	4.26870312122838
2007	4.33613679168286
2008	4.47733929081673
2009	4.65159901480152
2010	4.52155052774544
2011	4.34946759067568
2012	9.69570994602882
2013	11.1978507699298
2014	13.5007710461885
2015	15.9767540229859
2016	16.9909063937261
2017	15.8322787166088
2018	16.4142118666524
2019	16.4622079967728
2020	16.2151321759258
2021	17.1886379673381