Year	Number
2007-01-01	16
2008-01-01	16
2009-01-01	15
2010-01-01	10
2011-01-01	10
2012-01-01	10
2013-01-01	10
2014-01-01	10
2015-01-01	9
2016-01-01	7
2017-01-01	7