Year	current US$
2000	45.1019246
2001	45.69870857
2002	47.75388174
2003	53.58423118
2004	55.11992525
2005	51.59920941
2006	48.77014277
2007	50.79032218
2008	57.0828205
2009	54.43595021
2010	54.80134528
2011	54.06343507
2012	50.27417977
2013	51.29252319
2014	52.09712614
2015	38.71894162
2016	39.42717517
2017	39.96436967
2018	41.62905785
2019	41.8292331
2020	42.33021203
2021	42.32493386