Year	Number
2004-01-01	23.5749
2005-01-01	23.5183
2006-01-01	23.7823
2007-01-01	23.5953
2008-01-01	23.9546
2009-01-01	22.9648
2010-01-01	22.5032
2011-01-01	21.7013
2012-01-01	21.8095
2013-01-01	21.5414
2014-01-01	21.1045
2015-01-01	19.3233
2016-01-01	17.5794
2017-01-01	16.4058