Year	Number
2004-01-01	2.5152
2005-01-01	2.6205
2006-01-01	2.9108
2007-01-01	2.9667
2008-01-01	3.0113
2009-01-01	3.0469
2010-01-01	3.2447
2011-01-01	3.2595
2012-01-01	3.8864
2013-01-01	3.8595
2014-01-01	4.4011
2015-01-01	4.8946