Year	Number
2004-01-01	18
2005-01-01	19
2006-01-01	19
2007-01-01	19
2008-01-01	19
2009-01-01	19
2010-01-01	18
2011-01-01	19
2012-01-01	21
2013-01-01	46
2014-01-01	60
2015-01-01	59
2016-01-01	60
2017-01-01	43