Year	Number
2004-01-01	6
2005-01-01	5
2006-01-01	5
2007-01-01	5
2008-01-01	5
2009-01-01	6
2010-01-01	7
2011-01-01	6
2012-01-01	7
2013-01-01	8
2014-01-01	10
2015-01-01	11