Year Number 2004-01-01 42487 2005-01-01 39877 2006-01-01 35222 2007-01-01 29191 2008-01-01 24917 2009-01-01 20805 2010-01-01 17013 2011-01-01 17942 2012-01-01 19522 2013-01-01 21237 2014-01-01 22457 2015-01-01 23747 2016-01-01 24935