Year	Number
2004-01-01	7.7737
2005-01-01	9.4526
2006-01-01	11.2409
2007-01-01	15.1825
2008-01-01	19.2336
2009-01-01	19.7080
2010-01-01	19.8905
2011-01-01	20.0730
2012-01-01	20.2190
2013-01-01	19.8905
2014-01-01	18.7956
2015-01-01	18.8321
2016-01-01	18.5766