Year Number 2005-01-01 0.1320 2006-01-01 0.1358 2007-01-01 0.1436 2008-01-01 0.1436 2009-01-01 0.1630 2010-01-01 0.1863 2011-01-01 0.2173 2012-01-01 0.3842 2013-01-01 0.4153