Year	Number
2004-01-01	15.8251
2005-01-01	16.5891
2006-01-01	17.9948
2007-01-01	18.0724
2008-01-01	18.1993
2009-01-01	18.4955
2010-01-01	18.6436
2011-01-01	18.7588
2012-01-01	19.0103
2013-01-01	19.2290
2014-01-01	19.4241
2015-01-01	19.5816
2016-01-01	19.4875