Year	Number
2004-01-01	13892840
2005-01-01	15862958
2006-01-01	19388892
2007-01-01	22721833
2008-01-01	24753624
2009-01-01	24324999
2010-01-01	23857850
2011-01-01	27831528
2012-01-01	31994782
2013-01-01	36203459
2014-01-01	31695711