Year	Number
2004-01-01	16
2005-01-01	16
2006-01-01	16
2007-01-01	16
2008-01-01	17
2009-01-01	17
2010-01-01	17
2011-01-01	13
2012-01-01	14
2013-01-01	14
2014-01-01	13
2015-01-01	13
2016-01-01	12
2017-01-01	8