Year	Number
2004-01-01	31
2005-01-01	29
2006-01-01	28
2007-01-01	28
2008-01-01	30
2009-01-01	30
2010-01-01	31
2011-01-01	30
2012-01-01	29
2013-01-01	28
2014-01-01	26
2015-01-01	26
2016-01-01	27