Year	Number
2004-01-01	20.3090
2005-01-01	19.8583
2006-01-01	19.5747
2007-01-01	19.3723
2008-01-01	19.1384
2009-01-01	18.8175
2010-01-01	18.6517
2011-01-01	18.7973
2012-01-01	18.4810
2013-01-01	18.0361
2014-01-01	17.5144
2015-01-01	16.6901
2016-01-01	15.4941
2017-01-01	14.2122