Year Percent 2005-01-01 74.9 2006-01-01 75.4 2007-01-01 75.8 2008-01-01 75.4 2009-01-01 72.8 2010-01-01 72.5 2011-01-01 72.9 2012-01-01 73.0 2013-01-01 73.0 2014-01-01 73.6 2015-01-01 74.1 2016-01-01 74.7