Year Percent 2005-01-01 8.19327602404479 2006-01-01 8.08053287656067 2007-01-01 8.24005394293390 2008-01-01 8.75475416206920 2009-01-01 11.23954197487290 2010-01-01 10.52170058658450 2011-01-01 10.80282078339250 2012-01-01 10.37118801471420 2013-01-01 10.82009280520920 2014-01-01 10.79170648302850 2015-01-01 10.04798677558900 2016-01-01 8.77852577649573 2017-01-01 8.00339548443789