Year	current US$
2000	290.74332694
2001	287.81782147
2002	307.70025424
2003	349.97817958
2004	377.73934805
2005	387.41924796
2006	401.84028574
2007	356.09095934
2008	259.24794323
2009	222.20991744
2010	326.01453525
2011	327.10676682
2012	446.88944094
2013	440.16161938
2014	450.80858586
2015	450.46678189
2016	508.63568898
2017	538.0853119
2018	575.59878103
2019	563.84665949
2020	610.79777146
2021	549.72946441