Year	Number
2004-01-01	16117720
2005-01-01	22607289
2006-01-01	21550962
2007-01-01	23586142
2008-01-01	24255454
2009-01-01	24261901
2010-01-01	23632310
2011-01-01	26338770
2012-01-01	26921353
2013-01-01	26059096
2014-01-01	28567046
2015-01-01	30304074
2016-01-01	35272346
2017-01-01	30425588