Year Percent 2005-01-01 53.2278775697000 2006-01-01 55.0024050913434 2007-01-01 54.5164721102948 2008-01-01 53.8084584356425 2009-01-01 53.4646382906215 2010-01-01 53.4523799648394 2011-01-01 53.8295831372773 2012-01-01 54.9956778362810 2013-01-01 54.9893785429934 2014-01-01 54.9526999721858 2015-01-01 54.7158378069162 2016-01-01 54.9460326983008 2017-01-01 54.9251634032688