Year	Number
2004-01-01	42
2005-01-01	39
2006-01-01	36
2007-01-01	31
2008-01-01	32
2009-01-01	31
2010-01-01	32
2011-01-01	31
2012-01-01	31
2013-01-01	31
2014-01-01	31
2015-01-01	31
2016-01-01	30
2017-01-01	30