Year	current US$
2000	3.8737847961294265
2001	4.9637111363505095
2002	4.538994933709236
2003	6.765935782637577
2004	9.265971623166548
2005	11.017468642441555
2006	11.549014530758399
2007	12.067005102323673
2008	13.281665107223462
2009	11.816154624768245
2010	12.118231079906788
2011	14.068527755209411
2012	14.93891547395657
2013	15.484755132868028
2014	14.544894588217494
2015	14.023757889085742
2016	11.839584660743835
2017	12.494228364018593
2018	13.472647611563541
2019	14.795075535649675
2020	16.09448052691565
2021	16.629394376525518