Year	current US$
2000	234.01570072
2001	223.71595008
2002	237.53859845
2003	243.21370531
2004	225.48663452
2005	265.60152205
2006	342.81149148
2007	359.323069
2008	497.60072479
2009	473.46759129
2010	473.01145833
2011	503.73076838
2012	480.58835856
2013	522.2470304
2014	509.24089842
2015	586.02829447
2016	628.3073456
2017	623.40377799
2018	544.76450792
2019	558.42837875
2020	443.39554117
2021	432.91386299