Year	current US$
2000	40.4049138
2001	79.65982335
2002	84.78043688
2003	138.83809277
2004	239.90150468
2005	264.50413544
2006	296.16429674
2007	201.10398686
2008	206.9740913
2009	141.6651877
2010	162.20960105
2011	196.43943856
2012	224.09598932
2013	258.908689
2014	307.41569062
2015	296.41089457
2016	331.5949015
2017	362.54269645
2018	374.62160695
2019	401.33768512
2020	397.17002347
2021	473.66383591