Year Number 2008-01-01 1.5934 2009-01-01 0.6876 2010-01-01 0.6920 2011-01-01 0.6952 2012-01-01 0.6977 2013-01-01 0.6994 2014-01-01 0.6180 2015-01-01 0.5966 2016-01-01 0.5992 2017-01-01 0.5992