Year	Number
2004-01-01	5
2005-01-01	5
2006-01-01	6
2007-01-01	6
2008-01-01	6
2009-01-01	6
2010-01-01	6
2011-01-01	31
2012-01-01	31
2013-01-01	30
2014-01-01	27
2015-01-01	27
2016-01-01	27
2017-01-01	27