Year Percent 2005-01-01 33.400 2006-01-01 29.800 2007-01-01 29.800 2008-01-01 31.900 2009-01-01 33.900 2010-01-01 31.175 2011-01-01 30.825 2012-01-01 31.100 2013-01-01 31.100 2014-01-01 31.650 2015-01-01 33.225 2016-01-01 32.225 2017-01-01 30.475