Year	Number
2004-01-01	15.2749
2005-01-01	16.0253
2006-01-01	17.9678
2007-01-01	21.3769
2008-01-01	22.6688
2009-01-01	21.7447
2010-01-01	19.0798
2011-01-01	19.3510
2012-01-01	21.2354
2013-01-01	21.5634
2014-01-01	21.4221
2015-01-01	19.4186
2016-01-01	19.6450