Year	Number
2004-01-01	17.6421
2005-01-01	18.3927
2006-01-01	20.9176
2007-01-01	23.3884
2008-01-01	23.1323
2009-01-01	26.3957
2010-01-01	25.2262
2011-01-01	18.1045
2012-01-01	18.7510
2013-01-01	22.7244
2014-01-01	24.1138
2015-01-01	21.3828
2016-01-01	22.7267