Year Number 2004-01-01 2 2005-01-01 2 2006-01-01 2 2007-01-01 2 2008-01-01 2 2009-01-01 2 2010-01-01 2 2011-01-01 2 2012-01-01 2 2013-01-01 2 2014-01-01 2 2015-01-01 2 2016-01-01 2 2017-01-01 1