Year	current US$
2000	7.56729501
2001	13.20172034
2002	11.41983361
2003	14.4039654
2004	21.16213143
2005	24.30566207
2006	37.51770133
2007	53.74924084
2008	87.28489787
2009	81.23047577
2010	60.04417522
2011	78.94772675
2012	79.4772744
2013	88.63199818
2014	70.80124092
2015	50.9856203
2016	41.53681468
2017	52.22614463
2018	35.776171
2019	29.3503822
2020	29.06413971
2021	37.0907959