Year	Number
2004-01-01	13
2005-01-01	13
2006-01-01	13
2007-01-01	19
2008-01-01	21
2009-01-01	24
2010-01-01	29
2011-01-01	32
2012-01-01	33
2013-01-01	42
2014-01-01	50
2015-01-01	50