Year	Number
2004-01-01	4.3842
2005-01-01	5.8684
2006-01-01	7.5850
2007-01-01	10.4768
2008-01-01	13.2610
2009-01-01	15.6284
2010-01-01	16.2689
2011-01-01	21.3683
2012-01-01	21.8520
2013-01-01	22.9552
2014-01-01	22.7407
2015-01-01	23.3823
2016-01-01	23.9727