Year	current US$
2000	298.95173746
2001	280.22929491
2002	262.90304687
2003	246.16706496
2004	229.46874729
2005	213.58580375
2006	234.78602171
2007	255.59657254
2008	277.41030484
2009	300.66489575
2010	337.2685798
2011	359.62412838
2012	333.39897306
2013	319.8525309
2014	297.7301122
2015	296.42634721
2016	326.47727105
2017	341.29023182
2018	388.99340876
2019	370.07255969
2020	237.07729174
2021	186.44768788