Year	Number
2004-01-01	15
2005-01-01	14
2006-01-01	13
2007-01-01	11
2008-01-01	10
2009-01-01	10
2010-01-01	9
2011-01-01	9
2012-01-01	9
2013-01-01	9
2014-01-01	9
2015-01-01	8
2016-01-01	9
2017-01-01	9