Year	Number
2006-01-01	19
2007-01-01	19
2008-01-01	20
2009-01-01	20
2010-01-01	20
2011-01-01	10
2012-01-01	8
2013-01-01	10
2014-01-01	8
2015-01-01	9
2016-01-01	8