Year	Number
2004-01-01	51
2005-01-01	50
2006-01-01	51
2007-01-01	50
2008-01-01	52
2009-01-01	52
2010-01-01	53
2011-01-01	53
2012-01-01	55
2013-01-01	56
2014-01-01	56
2015-01-01	56
2016-01-01	57