Year	Number
2004-01-01	0.5130
2005-01-01	0.5072
2006-01-01	0.4984
2007-01-01	0.4908
2008-01-01	0.4783
2009-01-01	0.4670
2010-01-01	0.4542
2011-01-01	0.4386
2012-01-01	0.4276
2013-01-01	0.4128
2014-01-01	0.4031
2015-01-01	0.3924
2016-01-01	0.3788
2017-01-01	0.2277