Year	Number
2004-01-01	4
2005-01-01	4
2006-01-01	12
2007-01-01	16
2008-01-01	20
2009-01-01	22
2010-01-01	35
2011-01-01	36
2012-01-01	38
2013-01-01	38
2014-01-01	39
2015-01-01	41
2016-01-01	42