Year	current US$
2000	65.60530359
2001	61.56863766
2002	71.60832
2003	83.69945495
2004	91.23397411
2005	99.25660819
2006	108.81103625
2007	128.45045765
2008	141.32182899
2009	143.45559136
2010	53.03589441
2011	72.8714021
2012	63.38185096
2013	75.13743746
2014	65.94233163
2015	48.81063929
2016	47.10999856
2017	48.79734254
2018	48.82303796
2019	48.08965671
2020	45.44179275
2021	50.92123289