Year Percent 2001-01-01 50.663100000000000 2002-01-01 51.074700000000000 2003-01-01 51.519900000000000 2004-01-01 50.304700000000000 2005-01-01 50.305900000000000 2006-01-01 50.898600000000000 2007-01-01 52.674800000000000 2008-01-01 55.322200000000000 2009-01-01 61.538400000000000 2010-01-01 61.333200000000000 2011-01-01 57.828500000000000 2012-01-01 54.755800000000000 2013-01-01 51.156300000000000 2014-01-01 46.632600000000000 2015-01-01 47.077200000000000 2016-01-01 49.196000000000005