Year	current US$
2000	198.21309931
2001	207.89453971
2002	223.66616761
2003	284.63931275
2004	337.05703701
2005	353.57735942
2006	382.7484057
2007	448.10282848
2008	474.67368589
2009	435.53867455
2010	430.48080871
2011	461.88414378
2012	411.02863408
2013	405.57887043
2014	394.56627632
2015	352.45029442
2016	346.14654838
2017	347.30468882
2018	390.43201215
2019	385.65656984
2020	364.56194858
2021	411.53628166