Year	Number
2004-01-01	3
2005-01-01	3
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	5
2013-01-01	5
2014-01-01	5
2015-01-01	5