Year	current US$
2000	2.565625579285731
2001	2.2321529857845133
2002	2.4576672623247102
2003	4.566173131737219
2004	6.231053145544653
2005	10.440737243498459
2006	10.220398147242603
2007	11.379040852674695
2008	12.699229985248495
2009	13.999637037116766
2010	15.710640840128876
2011	16.67198144057771
2012	15.704893516805177
2013	15.977127281266192
2014	11.704023520751866
2015	10.352557526171793
2016	10.691771349246205
2017	11.752228197399209
2018	12.244339765383534
2019	12.67764899373272
2020	11.559027961263906
2021	13.247696614995128