Year	Number
2004-01-01	4.0263
2005-01-01	4.1261
2006-01-01	4.3478
2007-01-01	4.8859
2008-01-01	5.3484
2009-01-01	5.7136
2010-01-01	6.0130
2011-01-01	6.1488
2012-01-01	6.6560
2013-01-01	6.7605
2014-01-01	6.8438
2015-01-01	6.6231
2016-01-01	6.7718