Year	Number
2004-01-01	57
2005-01-01	58
2006-01-01	57
2007-01-01	58
2008-01-01	57
2009-01-01	57
2010-01-01	57
2011-01-01	56
2012-01-01	55
2013-01-01	53
2014-01-01	52
2015-01-01	49
2016-01-01	50
2017-01-01	49