Year Percent 2005-01-01 0.0000000000000000 2006-01-01 0.0000000000000000 2007-01-01 5.3375900000000005 2008-01-01 6.5576899999999990 2009-01-01 7.2828000000000000 2010-01-01 8.0984300000000000 2011-01-01 8.8471000000000000 2012-01-01 9.7317800000000000 2013-01-01 9.4841900000000000 2014-01-01 9.4001100000000000 2015-01-01 9.4053800000000010 2016-01-01 9.0568900000000000 2017-01-01 9.0932200000000000