Year Percent 2000-01-01 58.4981049785348 2001-01-01 59.0372895081647 2002-01-01 60.0602322227763 2003-01-01 59.3981361671852 2004-01-01 60.0488167550559 2005-01-01 59.8922910393703 2006-01-01 60.0215896958332 2007-01-01 60.1342388982666 2008-01-01 59.7716934254876 2009-01-01 58.7750408977050 2010-01-01 58.8665198628141 2011-01-01 59.2588409297506 2012-01-01 59.6182395108711 2013-01-01 59.8016330050637 2014-01-01 60.5127888441009 2015-01-01 60.5399700455469 2016-01-01 60.5619912894476 2017-01-01 60.8333802147226