Year	current US$
2000	5.82561302
2001	7.70397997
2002	6.6404686
2003	6.02923203
2004	9.11969662
2005	11.43010426
2006	14.48706532
2007	15.68034935
2008	15.07347488
2009	18.82117844
2010	25.12049484
2011	23.81056213
2012	20.57489777
2013	20.8417263
2014	18.59082222
2015	18.2036705
2016	19.16795921
2017	19.77140808
2018	19.27294159
2019	22.95755196
2020	27.07072449
2021	24.26920891