Year	Number
2004-01-01	25.0611
2005-01-01	24.5063
2006-01-01	23.9150
2007-01-01	23.3487
2008-01-01	22.8097
2009-01-01	22.3127
2010-01-01	21.8706
2011-01-01	21.5011
2012-01-01	21.1852
2013-01-01	20.9048
2014-01-01	20.6431
2015-01-01	19.6881
2016-01-01	16.0139
2017-01-01	16.0139