Year Percent 1996-01-01 0.43711400000000006 1997-01-01 0.50933700000000000 1998-01-01 0.53021900000000000 1999-01-01 0.67301099999999990 2000-01-01 0.82528700000000010 2001-01-01 1.11773000000000000 2002-01-01 1.59757000000000020 2003-01-01 1.62470000000000000 2004-01-01 1.80005000000000000 2005-01-01 2.73088000000000000 2006-01-01 2.05205000000000000 2007-01-01 2.05205000000000000 2008-01-01 1.86182999999999990 2009-01-01 2.40029000000000000 2010-01-01 2.18838000000000000 2011-01-01 1.99243000000000000 2012-01-01 2.24839000000000000 2013-01-01 2.04943000000000000 2014-01-01 1.89283000000000000 2015-01-01 2.28585000000000000