Year	Number
2004-01-01	2.0605
2005-01-01	2.2359
2006-01-01	2.4551
2007-01-01	2.6743
2008-01-01	2.8935
2009-01-01	3.1127
2010-01-01	3.3757
2011-01-01	3.6388
2012-01-01	3.6826
2013-01-01	4.0333
2014-01-01	4.2087
2015-01-01	4.2964
2016-01-01	4.3840