Year	Number
2004-01-01	771
2005-01-01	4780
2006-01-01	8409
2007-01-01	15197
2008-01-01	17650
2009-01-01	16546
2010-01-01	20000
2011-01-01	20329
2012-01-01	22334
2013-01-01	25843
2014-01-01	27392
2015-01-01	22179
2016-01-01	17370
2017-01-01	14023