Year Percent 2006-01-01 0.99 2007-01-01 0.88 2008-01-01 0.92 2009-01-01 0.80 2010-01-01 0.83 2011-01-01 0.78 2012-01-01 0.75 2013-01-01 0.78 2014-01-01 0.77 2015-01-01 0.74 2016-01-01 0.75