Year	current US$
2000	259.3835144
2001	271.16744995
2002	308.3371582
2003	287.2850647
2004	293.60290527
2005	324.55722046
2006	321.82662964
2007	355.66372681
2008	395.50680542
2009	370.04714966
2010	366.41027832
2011	393.21112061
2012	401.84506226
2013	405.39501953
2014	368.81384277
2015	389.39382935
2016	392.77981567
2017	433.48513794
2018	438.918396
2019	487.60290527
2020	469.00775146
2021	505.40463257