Year	Number
2004-01-01	968
2005-01-01	1566
2006-01-01	1922
2007-01-01	2491
2008-01-01	2845
2009-01-01	3475
2010-01-01	4046
2011-01-01	4497
2012-01-01	5387
2013-01-01	6315
2014-01-01	8050
2015-01-01	13773
2016-01-01	16639