Year	Number
2004-01-01	11.7975
2005-01-01	11.8018
2006-01-01	11.7966
2007-01-01	14.7291
2008-01-01	17.6475
2009-01-01	17.6131
2010-01-01	17.5778
2011-01-01	20.4618
2012-01-01	20.4148
2013-01-01	20.3645
2014-01-01	20.3241
2015-01-01	20.2873
2016-01-01	20.2597