Year	Number
2004-01-01	6469373
2005-01-01	7980231
2006-01-01	10269192
2007-01-01	11674407
2008-01-01	11824435
2009-01-01	14737478
2010-01-01	13067586
2011-01-01	15444065
2012-01-01	16262173
2013-01-01	17313275
2014-01-01	18760294
2015-01-01	19768969
2016-01-01	21126820
2017-01-01	21612261