Year Percent 1998-01-01 50.6308 1999-01-01 40.4865 2000-01-01 31.6000 2001-01-01 47.3000 2002-01-01 51.8231 2003-01-01 42.9190 2004-01-01 62.5185 2005-01-01 56.8513 2006-01-01 42.8711 2007-01-01 52.6667 2008-01-01 54.8872 2009-01-01 66.4215 2010-01-01 87.2886 2011-01-01 74.5590 2012-01-01 52.0033 2013-01-01 75.5201 2014-01-01 78.8062 2015-01-01 75.9255 2016-01-01 70.9071