Year	Number
2004-01-01	0.1854
2005-01-01	0.1830
2006-01-01	0.1864
2007-01-01	0.1842
2008-01-01	0.1769
2009-01-01	0.1684
2010-01-01	0.1660
2011-01-01	0.1647
2012-01-01	0.1429
2013-01-01	0.1317
2014-01-01	0.1220
2015-01-01	0.1009
2016-01-01	0.0743