Year Number 2004-01-01 13589 2005-01-01 15357 2006-01-01 16432 2007-01-01 17422 2008-01-01 17812 2009-01-01 17171 2010-01-01 14740 2011-01-01 14919 2012-01-01 15055 2013-01-01 14900 2014-01-01 17115 2015-01-01 17330 2016-01-01 16956