Year	current US$
2000	180.29981014
2001	157.50158732
2002	140.75732533
2003	142.54154863
2004	167.20724367
2005	223.61438001
2006	275.67172597
2007	344.95902616
2008	396.30596021
2009	400.63167206
2010	489.18817514
2011	567.10961068
2012	538.97215718
2013	541.8337461
2014	565.66493764
2015	443.40419998
2016	452.59310515
2017	545.49024278
2018	507.80601267
2019	502.71925938
2020	390.39886252
2021	413.57415201