Year	Number
2004-01-01	0.8547
2005-01-01	1.4532
2006-01-01	3.0434
2007-01-01	4.4133
2008-01-01	6.2587
2009-01-01	8.3792
2010-01-01	10.4677
2011-01-01	12.7784
2012-01-01	15.2444
2013-01-01	17.0362
2014-01-01	18.2182
2015-01-01	18.8292