Year	Number
2004-01-01	21.6929
2005-01-01	22.7944
2006-01-01	25.4043
2007-01-01	28.5219
2008-01-01	32.9436
2009-01-01	36.8711
2010-01-01	41.9076
2011-01-01	47.5168
2012-01-01	50.9193
2013-01-01	56.2096
2014-01-01	58.8407
2015-01-01	60.5544
2016-01-01	60.1037
2017-01-01	60.1037