Year	Number
2004-01-01	21
2005-01-01	21
2006-01-01	23
2007-01-01	24
2008-01-01	28
2009-01-01	30
2010-01-01	31
2011-01-01	31
2012-01-01	35
2013-01-01	45
2014-01-01	47
2015-01-01	48
2016-01-01	53