Year	Number
2004-01-01	1447
2005-01-01	1563
2006-01-01	1913
2007-01-01	2295
2008-01-01	2792
2009-01-01	3214
2010-01-01	3819
2011-01-01	4432
2012-01-01	5536
2013-01-01	6012
2014-01-01	8156
2015-01-01	17888