Year	Number
2004-01-01	1.8564
2005-01-01	1.9117
2006-01-01	2.0152
2007-01-01	2.2171
2008-01-01	2.3959
2009-01-01	2.5154
2010-01-01	2.5828
2011-01-01	2.6440
2012-01-01	2.6701
2013-01-01	2.7174
2014-01-01	2.7696
2015-01-01	2.8560