Year Percent 1999-01-01 0.08700000000000000 2000-01-01 0.10200000000000000 2001-01-01 0.10549900000000000 2002-01-01 0.10918399999999999 2003-01-01 0.12292900000000000 2004-01-01 0.14591200000000000 2005-01-01 0.15633300000000000 2006-01-01 0.16470900000000000 2007-01-01 0.25563900000000000 2008-01-01 0.22736900000000002 2009-01-01 0.22427500000000000 2010-01-01 0.27962300000000000 2011-01-01 0.24645100000000003 2012-01-01 0.24674800000000000 2013-01-01 0.25550600000000000 2014-01-01 0.27594400000000000 2015-01-01 0.27346200000000000