Year	Number
2004-01-01	16951465
2005-01-01	17452220
2006-01-01	20232378
2007-01-01	22238952
2008-01-01	24584507
2009-01-01	26325952
2010-01-01	28007361
2011-01-01	30410578
2012-01-01	32048208
2013-01-01	33630842
2014-01-01	35151871
2015-01-01	36729884
2016-01-01	36879613