Year	Number
2004-01-01	15
2005-01-01	16
2006-01-01	19
2007-01-01	22
2008-01-01	22
2009-01-01	26
2010-01-01	25
2011-01-01	17
2012-01-01	18
2013-01-01	23
2014-01-01	25
2015-01-01	22
2016-01-01	24