Year	Number
2004-01-01	51
2005-01-01	51
2006-01-01	54
2007-01-01	54
2008-01-01	55
2009-01-01	54
2010-01-01	54
2011-01-01	58
2012-01-01	59
2013-01-01	60
2014-01-01	60
2015-01-01	60
2016-01-01	57