Year	current US$
2000	5.89590777
2001	6.22665348
2002	6.44098264
2003	7.12385703
2004	7.07264168
2005	8.22010583
2006	9.47544798
2007	12.27986803
2008	14.21174629
2009	15.31607248
2010	17.06763944
2011	17.65128708
2012	20.97498849
2013	22.86794341
2014	27.37998824
2015	28.79389319
2016	31.79279864
2017	28.68562276
2018	32.61632539
2019	39.57313559
2020	42.78964632
2021	46.13707075