Year	Number
2004-01-01	0
2005-01-01	0
2006-01-01	0
2007-01-01	1
2008-01-01	2
2009-01-01	4
2010-01-01	4
2011-01-01	5
2012-01-01	5
2013-01-01	1
2014-01-01	0
2015-01-01	2
2016-01-01	2
2017-01-01	2