Year Percent 1999-01-01 16.400 2000-01-01 18.550 2001-01-01 18.750 2002-01-01 18.700 2003-01-01 17.775 2004-01-01 19.200 2005-01-01 17.225 2006-01-01 14.775 2007-01-01 12.700 2008-01-01 10.950 2009-01-01 12.850 2010-01-01 14.650 2011-01-01 13.650 2012-01-01 14.550 2013-01-01 14.575 2014-01-01 13.700 2015-01-01 12.950 2016-01-01 10.825 2017-01-01 8.475