Year	Number
2004-01-01	27
2005-01-01	29
2006-01-01	31
2007-01-01	34
2008-01-01	41
2009-01-01	48
2010-01-01	52
2011-01-01	56
2012-01-01	56
2013-01-01	56
2014-01-01	52
2015-01-01	56
2016-01-01	60