Year	current US$
2000	8.08632275
2001	8.59793185
2002	8.06892881
2003	8.47908056
2004	9.9474515
2005	11.14593432
2006	11.71145486
2007	12.29604274
2008	16.32428496
2009	14.2471592
2010	14.04070276
2011	16.01448499
2012	22.15683888
2013	29.6040181
2014	35.95730051
2015	35.05811228
2016	36.50642366
2017	37.45113431
2018	39.38009298
2019	37.53267756
2020	38.40298632
2021	41.2708135