Year	Number
2004-01-01	6.0647
2005-01-01	6.0526
2006-01-01	6.2070
2007-01-01	6.3551
2008-01-01	6.4957
2009-01-01	6.6318
2010-01-01	6.7646
2011-01-01	7.4577
2012-01-01	7.7396
2013-01-01	8.2010
2014-01-01	8.4603
2015-01-01	8.5295
2016-01-01	8.4278
2017-01-01	8.4278