Year	Number
2004-01-01	21399433
2005-01-01	22788672
2006-01-01	25009133
2007-01-01	27422627
2008-01-01	28860690
2009-01-01	23471992
2010-01-01	26762282
2011-01-01	28839883
2012-01-01	31054876
2013-01-01	32453187
2014-01-01	34114611
2015-01-01	35004959
2016-01-01	35717204