Year	Number
2004-01-01	19.9664
2005-01-01	21.7050
2006-01-01	21.6498
2007-01-01	18.0052
2008-01-01	21.5685
2009-01-01	35.8693
2010-01-01	30.3988
2011-01-01	46.3121
2012-01-01	46.1025
2013-01-01	49.4047
2014-01-01	47.3929
2015-01-01	41.9059
2016-01-01	39.9517
2017-01-01	36.4777