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