Year	Number
2004-01-01	2.3364
2005-01-01	2.4922
2006-01-01	2.8037
2007-01-01	3.1153
2008-01-01	3.3100
2009-01-01	3.7383
2010-01-01	4.3224
2011-01-01	4.8676
2012-01-01	5.4517
2013-01-01	6.6589
2014-01-01	6.6978
2015-01-01	6.9704
2016-01-01	7.1651