Year	Number
2004-01-01	3.2535
2005-01-01	3.7289
2006-01-01	4.1820
2007-01-01	5.5181
2008-01-01	5.8606
2009-01-01	5.8326
2010-01-01	5.7758
2011-01-01	5.8748
2012-01-01	5.9670
2013-01-01	5.9449
2014-01-01	6.1452
2015-01-01	6.1040
2016-01-01	6.1189
2017-01-01	6.4354