Year	current US$
2000	14.72714445
2001	14.62774659
2002	15.8587615
2003	16.72405596
2004	16.36468574
2005	17.87408953
2006	19.3989401
2007	22.47012982
2008	25.99625421
2009	25.03115894
2010	20.72132354
2011	29.0943996
2012	34.21897824
2013	51.79291559
2014	55.8949799
2015	46.8001936
2016	40.85369923
2017	25.58703426
2018	26.64660778
2019	25.0692531
2020	24.60276358
2021	22.31469092