Year	Number
2004-01-01	2.5857
2005-01-01	2.6822
2006-01-01	2.6788
2007-01-01	2.6582
2008-01-01	2.5634
2009-01-01	2.1991
2010-01-01	1.5829
2011-01-01	1.0840
2012-01-01	0.7215
2013-01-01	0.6162
2014-01-01	0.5110
2015-01-01	0.3729
2016-01-01	0.3263
2017-01-01	0.2969