Year	Number
2004-01-01	1.8452
2005-01-01	2.1314
2006-01-01	2.6789
2007-01-01	3.4187
2008-01-01	4.3192
2009-01-01	5.1411
2010-01-01	5.4894
2011-01-01	6.1300
2012-01-01	6.9211
2013-01-01	7.4525
2014-01-01	7.7092
2015-01-01	7.5937
2016-01-01	7.8307
2017-01-01	8.2788