Year	Number
2004-01-01	5866314
2005-01-01	6935071
2006-01-01	8522021
2007-01-01	10214674
2008-01-01	11688415
2009-01-01	12354995
2010-01-01	13050802
2011-01-01	14381878
2012-01-01	15673674
2013-01-01	14406263
2014-01-01	15036579
2015-01-01	17466094
2016-01-01	18060560
2017-01-01	18553808