Year	current US$
2000	0
2001	0
2002	0
2003	1
2004	0
2005	0
2006	1
2007	1
2008	1
2009	2
2010	2
2011	2
2012	4
2013	2
2014	3
2015	2
2016	1
2017	1
2018	1
2019	1
2020	1
2021	1