Year Percent 1996-01-01 15.9834 1997-01-01 17.6699 1998-01-01 16.0323 1999-01-01 13.2639 2000-01-01 14.6517 2001-01-01 14.4822 2002-01-01 14.5232 2003-01-01 14.5706 2004-01-01 18.1918 2005-01-01 27.5370 2006-01-01 21.0694 2007-01-01 20.7560 2008-01-01 16.5462 2009-01-01 10.7986 2010-01-01 10.7469 2011-01-01 11.6209 2012-01-01 12.1217 2013-01-01 13.1398 2014-01-01 14.5301 2015-01-01 14.7648 2016-01-01 11.8329