Year	current US$
2000	2.54414131
2001	2.84630006
2002	2.01085915
2003	1.58255877
2004	1.72903932
2005	1.93634437
2006	2.32331005
2007	2.57683024
2008	2.76163267
2009	2.50571964
2010	2.99260234
2011	3.08231427
2012	3.0797563
2013	3.21439904
2014	3.1684871
2015	2.93572112
2016	2.96719456
2017	2.99247609
2018	3.4217751
2019	3.81970424
2020	3.72825107
2021	3.87043457