Year Number 2008-01-01 0.6840 2009-01-01 0.7347 2010-01-01 0.7604 2011-01-01 0.5527 2012-01-01 0.5955 2013-01-01 0.6148 2014-01-01 0.5308 2015-01-01 0.5285 2016-01-01 0.5536 2017-01-01 0.5698