Year	Number
2004-01-01	14
2005-01-01	16
2006-01-01	17
2007-01-01	18
2008-01-01	18
2009-01-01	18
2010-01-01	20
2011-01-01	22
2012-01-01	23
2013-01-01	29
2014-01-01	34
2015-01-01	34