Year Number 2004-01-01 5042.0 2005-01-01 6819.0 2006-01-01 5512.0 2007-01-01 7849.0 2008-01-01 9137.0 2009-01-01 10736.0 2010-01-01 11183.0 2011-01-01 10471.0 2012-01-01 11843.0 2013-01-01 13691.0 2014-01-01 14200.0 2015-01-01 7876.0 2016-01-01 6840.0 2017-01-01 10317.3