Year	Number
2004-01-01	353
2005-01-01	558
2006-01-01	931
2007-01-01	1309
2008-01-01	1729
2009-01-01	2040
2010-01-01	2246
2011-01-01	2389
2012-01-01	2699
2013-01-01	3163
2014-01-01	3697
2015-01-01	4291