Year	Number
2004-01-01	16.1455
2005-01-01	16.8475
2006-01-01	18.2833
2007-01-01	21.2827
2008-01-01	23.4703
2009-01-01	24.6191
2010-01-01	25.0658
2011-01-01	20.8220
2012-01-01	21.1092
2013-01-01	20.1197
2014-01-01	20.4789
2015-01-01	19.4094
2016-01-01	18.8508
2017-01-01	17.9729