Year Percent 1998-01-01 61.482500000000000 1999-01-01 61.306600000000000 2000-01-01 54.600000000000000 2001-01-01 56.200000000000000 2002-01-01 49.858700000000000 2003-01-01 51.877800000000000 2004-01-01 54.227900000000000 2005-01-01 52.419800000000000 2006-01-01 60.697100000000000 2007-01-01 59.456500000000000 2008-01-01 36.289300000000000 2009-01-01 43.638800000000000 2010-01-01 47.758800000000000 2011-01-01 45.533100000000000 2012-01-01 46.277900000000000 2013-01-01 49.291000000000004 2014-01-01 40.791300000000000 2015-01-01 36.717100000000000 2016-01-01 49.752900000000000