Year	current US$
2000	15.01472415
2001	13.95836972
2002	14.92120539
2003	16.1915266
2004	18.56804124
2005	13.95388361
2006	11.57826114
2007	16.3626133
2008	16.49831141
2009	17.40270576
2010	15.84939409
2011	14.65085719
2012	14.97087045
2013	16.23321107
2014	21.6432869
2015	21.68654022
2016	19.36684647
2017	21.33186933
2018	23.69616758
2019	25.27467643
2020	23.79496098
2021	23.89280118