Year Percent 2005-01-01 49.9856158478676 2006-01-01 50.8999801269747 2007-01-01 51.9880162964072 2008-01-01 52.7715364015280 2009-01-01 52.3839908786703 2010-01-01 52.6968627732379 2011-01-01 53.6246884751715 2012-01-01 53.9201009383290 2013-01-01 54.0404110499719