Year	Number
2004-01-01	2.6962
2005-01-01	3.0632
2006-01-01	3.2387
2007-01-01	3.7332
2008-01-01	3.9729
2009-01-01	4.1165
2010-01-01	4.1643
2011-01-01	4.2921
2012-01-01	4.5473
2013-01-01	4.5313
2014-01-01	4.5650
2015-01-01	4.4214
2016-01-01	4.0862
2017-01-01	3.6233