Year Percent 1996-01-01 40.794100000000000 1997-01-01 39.890900000000000 1998-01-01 35.205800000000000 1999-01-01 36.513000000000005 2000-01-01 36.831600000000000 2001-01-01 36.585600000000000 2002-01-01 30.327800000000000 2003-01-01 29.802200000000000 2004-01-01 32.671900000000000 2005-01-01 31.213800000000000 2006-01-01 31.871500000000000 2007-01-01 26.085200000000000 2008-01-01 25.878400000000000 2009-01-01 27.699800000000000 2010-01-01 32.603800000000000 2011-01-01 36.776400000000000 2012-01-01 31.354000000000000 2013-01-01 30.470800000000000 2014-01-01 31.189700000000000 2015-01-01 38.281000000000000 2016-01-01 35.547300000000000