Year Percent 2005-01-01 76.0 2006-01-01 76.5 2007-01-01 76.8 2008-01-01 76.3 2009-01-01 73.6 2010-01-01 73.1 2011-01-01 73.5 2012-01-01 73.8 2013-01-01 73.9 2014-01-01 74.5 2015-01-01 74.9 2016-01-01 75.5