Year	current US$
2000	8.13177445
2001	8.18413279
2002	8.63204228
2003	11.17042951
2004	14.3859579
2005	14.65459347
2006	18.28135932
2007	22.04541546
2008	22.36572585
2009	29.96046506
2010	28.72319663
2011	35.86275503
2012	38.22902982
2013	35.85394326
2014	35.55601087
2015	35.68746651
2016	36.33754485
2017	28.94977597
2018	44.90189127
2019	48.60819867
2020	43.58519527
2021	44.63120762