Year	Number
2004-01-01	0.4163
2005-01-01	0.6267
2006-01-01	0.8397
2007-01-01	1.6165
2008-01-01	2.3091
2009-01-01	2.5784
2010-01-01	2.8170
2011-01-01	3.0040
2012-01-01	3.2048
2013-01-01	3.3207
2014-01-01	3.4100
2015-01-01	3.3878
2016-01-01	3.5415
2017-01-01	3.5923