Year	current US$
2000	5.1881621
2001	4.57737998
2002	5.26815691
2003	6.03392247
2004	6.92151407
2005	6.58931709
2006	7.08326604
2007	8.35876039
2008	10.020653
2009	10.88843755
2010	9.57931123
2011	9.55399052
2012	12.55167152
2013	14.00256412
2014	16.52976838
2015	15.61912109
2016	17.05355258
2017	19.71050585
2018	20.62832043
2019	22.24538715
2020	31.30802898
2021	26.90036392