Year	Number
2004-01-01	2.9253
2005-01-01	3.1178
2006-01-01	3.3521
2007-01-01	3.3931
2008-01-01	3.5251
2009-01-01	3.5233
2010-01-01	3.9171
2011-01-01	4.0146
2012-01-01	3.9484
2013-01-01	3.9340
2014-01-01	4.0956
2015-01-01	4.1213
2016-01-01	4.2798