Year	Number
2004-01-01	22
2005-01-01	22
2006-01-01	22
2007-01-01	24
2008-01-01	25
2009-01-01	27
2010-01-01	28
2011-01-01	31
2012-01-01	32
2013-01-01	34
2014-01-01	34
2015-01-01	36