Year	current US$
2000	7.58348761
2001	5.42539137
2002	10.79661256
2003	7.37425197
2004	10.04199767
2005	7.13369177
2006	6.97427579
2007	9.43422626
2008	8.77188842
2009	10.38695136
2010	10.04283422
2011	12.0666324
2012	14.15351259
2013	8.79276702
2014	8.71844457
2015	7.71417506
2016	7.79602024
2017	6.56782139
2018	8.77990887
2019	3.18188365
2020	32.3898359
2021	55.24669733