Year	current US$
2000	5.27461878
2001	5.98694151
2002	5.42231407
2003	7.80069592
2004	6.03814452
2005	6.02864784
2006	6.25658762
2007	8.14952621
2008	7.37780781
2009	5.95434949
2010	8.58040727
2011	8.67432045
2012	7.51114264
2013	6.86937823
2014	9.04027645
2015	9.06770004
2016	11.02044581
2017	11.30932709
2018	7.70671218
2019	3.49727992
2020	3.19005892
2021	3.71035207