Year	Number
2004-01-01	37
2005-01-01	36
2006-01-01	35
2007-01-01	35
2008-01-01	34
2009-01-01	32
2010-01-01	32
2011-01-01	30
2012-01-01	32
2013-01-01	33
2014-01-01	33
2015-01-01	34
2016-01-01	34