Year	Number
2004-01-01	0.3736
2005-01-01	0.5933
2006-01-01	0.9377
2007-01-01	1.2529
2008-01-01	1.4911
2009-01-01	2.2416
2010-01-01	2.4009
2011-01-01	2.2309
2012-01-01	2.1530
2013-01-01	2.2775
2014-01-01	2.3322
2015-01-01	2.1910
2016-01-01	2.1382
2017-01-01	2.1382