Year	Number
2004-01-01	16.6852
2005-01-01	17.5631
2006-01-01	17.6517
2007-01-01	18.3249
2008-01-01	19.0579
2009-01-01	19.8129
2010-01-01	20.9281
2011-01-01	20.8018
2012-01-01	20.9543
2013-01-01	21.8395
2014-01-01	22.0678
2015-01-01	21.8204
2016-01-01	21.5538
2017-01-01	20.9232