Year Percent 1998-01-01 11.1000 1999-01-01 11.5000 2000-01-01 11.6000 2001-01-01 14.7000 2002-01-01 13.4000 2003-01-01 9.3000 2004-01-01 13.9000 2005-01-01 16.2000 2006-01-01 15.8000 2007-01-01 15.7000 2008-01-01 13.8000 2009-01-01 18.2000 2010-01-01 19.1330 2011-01-01 17.4095 2012-01-01 18.5587 2013-01-01 18.4543 2014-01-01 17.9264 2015-01-01 17.8067 2016-01-01 17.7549