Year Number 2004-01-01 6 2005-01-01 6 2006-01-01 6 2007-01-01 6 2008-01-01 6 2009-01-01 6 2010-01-01 6 2011-01-01 6 2012-01-01 6 2013-01-01 6 2014-01-01 8