Year	Number
2004-01-01	27
2005-01-01	27
2006-01-01	26
2007-01-01	26
2008-01-01	25
2009-01-01	27
2010-01-01	28
2011-01-01	29
2012-01-01	29
2013-01-01	29
2014-01-01	29
2015-01-01	25
2016-01-01	24
2017-01-01	24