Year	Number
2004-01-01	2
2005-01-01	2
2006-01-01	2
2007-01-01	4
2008-01-01	4
2009-01-01	6
2010-01-01	8
2011-01-01	29
2012-01-01	24
2013-01-01	26
2014-01-01	23
2015-01-01	23
2016-01-01	24