Year	Number
2004-01-01	14
2005-01-01	14
2006-01-01	14
2007-01-01	14
2008-01-01	14
2009-01-01	14
2010-01-01	15
2011-01-01	16
2012-01-01	19
2013-01-01	21
2014-01-01	21
2015-01-01	21