Year	Number
2004-01-01	1595
2005-01-01	1639
2006-01-01	2053
2007-01-01	3076
2008-01-01	1494
2009-01-01	4762
2010-01-01	4094
2011-01-01	5282
2012-01-01	6602
2013-01-01	5267