Year	current US$
2000	3.40762835
2001	3.15598848
2002	3.62882444
2003	5.39479766
2004	6.79436003
2005	6.62270339
2006	6.2048979
2007	5.77355194
2008	4.84211581
2009	4.54359611
2010	4.60444168
2011	4.89970349
2012	3.11544408
2013	6.35372494
2014	7.29846171
2015	6.6510194
2016	9.06640071
2017	9.36910677
2018	9.85823548
2019	9.4038729
2020	11.54284223
2021	11.7677976