Year	Number
2004-01-01	35
2005-01-01	36
2006-01-01	37
2007-01-01	37
2008-01-01	37
2009-01-01	39
2010-01-01	41
2011-01-01	44
2012-01-01	43
2013-01-01	44
2014-01-01	45
2015-01-01	46
2016-01-01	45
2017-01-01	45