Year	Number
2004-01-01	6121
2005-01-01	6521
2006-01-01	7362
2007-01-01	8377
2008-01-01	9808
2009-01-01	11124
2010-01-01	12806
2011-01-01	14707
2012-01-01	15954
2013-01-01	17822
2014-01-01	18880
2015-01-01	19667
2016-01-01	19750
2017-01-01	19750