Year Number 2004-01-01 11 2005-01-01 11 2006-01-01 10 2007-01-01 11 2008-01-01 11 2009-01-01 11 2010-01-01 11 2011-01-01 11 2012-01-01 10 2013-01-01 10 2014-01-01 10 2015-01-01 10 2016-01-01 10