Year	Number
2004-01-01	22
2005-01-01	23
2006-01-01	23
2007-01-01	23
2008-01-01	22
2009-01-01	22
2010-01-01	22
2011-01-01	24
2012-01-01	24
2013-01-01	24
2014-01-01	25
2015-01-01	25