Year	current US$
2000	5.36601635
2001	15.30970852
2002	17.26381428
2003	20.10333635
2004	27.65380819
2005	28.2598174
2006	28.16552125
2007	36.58735646
2008	44.97102656
2009	34.20689943
2010	33.48183193
2011	39.47774087
2012	39.66889999
2013	50.58776642
2014	55.79636629
2015	53.78350541
2016	49.1423298
2017	57.11024415
2018	45.26545312
2019	32.75403445
2020	22.94432086
2021	23.96489183