Year	current US$
2000	318.90114007
2001	301.76147649
2002	96.79939026
2003	117.2963617
2004	130.01612371
2005	185.23279378
2006	213.53472296
2007	258.80385418
2008	326.6979534
2009	310.77228696
2010	399.22379806
2011	470.18457367
2012	504.64706327
2013	508.86614832
2014	436.02444003
2015	503.30411813
2016	431.91469797
2017	524.60606618
2018	500.06907774
2019	398.40377207
2020	319.87004752
2021	371.24411485