Year	Number
2004-01-01	2.2366
2005-01-01	2.3828
2006-01-01	2.6901
2007-01-01	3.0610
2008-01-01	3.5839
2009-01-01	4.0648
2010-01-01	4.6794
2011-01-01	5.3740
2012-01-01	5.8297
2013-01-01	6.5122
2014-01-01	6.8988
2015-01-01	7.1864
2016-01-01	7.2167
2017-01-01	7.2167