Year	Number
2004-01-01	16372.0
2005-01-01	17864.0
2006-01-01	17576.0
2007-01-01	36872.0
2008-01-01	39851.0
2009-01-01	42306.0
2010-01-01	43053.0
2011-01-01	44715.0
2012-01-01	44031.0
2013-01-01	48532.0
2014-01-01	49210.0
2015-01-01	23475.0
2016-01-01	19588.0
2017-01-01	25240.7