Year	Number
2004-01-01	31
2005-01-01	39
2006-01-01	39
2007-01-01	38
2008-01-01	43
2009-01-01	45
2010-01-01	48
2011-01-01	50
2012-01-01	52
2013-01-01	56
2014-01-01	55
2015-01-01	54
2016-01-01	50
2017-01-01	49