Year	current US$
2000	15.38957067
2001	15.16442313
2002	16.60934649
2003	20.89132483
2004	22.74842127
2005	24.09948975
2006	27.41877336
2007	29.8045726
2008	31.8693763
2009	32.33344893
2010	43.86721986
2011	43.75870018
2012	45.39666617
2013	48.87386045
2014	50.45223913
2015	41.87617419
2016	45.22309718
2017	49.05252187
2018	51.25836974
2019	51.11134227
2020	44.83558803
2021	50.3191532