Year Percent 1998-01-01 61.092900000000000 1999-01-01 60.802400000000000 2000-01-01 62.600000000000000 2001-01-01 62.700000000000000 2002-01-01 60.589900000000000 2003-01-01 53.042300000000000 2004-01-01 58.251999999999995 2005-01-01 48.890700000000000 2006-01-01 44.277000000000000 2007-01-01 44.895700000000000 2008-01-01 53.793500000000000 2009-01-01 53.913700000000000 2010-01-01 58.104500000000000 2011-01-01 63.135400000000000 2012-01-01 57.909900000000000 2013-01-01 52.961800000000000 2014-01-01 61.961900000000000 2015-01-01 63.984400000000000 2016-01-01 62.951800000000000