Year	Number
2004-01-01	36
2005-01-01	37
2006-01-01	40
2007-01-01	41
2008-01-01	44
2009-01-01	41
2010-01-01	40
2011-01-01	38
2012-01-01	35
2013-01-01	34
2014-01-01	34
2015-01-01	33
2016-01-01	32
2017-01-01	32