Year	Number
2004-01-01	23
2005-01-01	23
2006-01-01	24
2007-01-01	25
2008-01-01	26
2009-01-01	27
2010-01-01	28
2011-01-01	32
2012-01-01	34
2013-01-01	37
2014-01-01	39
2015-01-01	40
2016-01-01	40
2017-01-01	40