Year Percent 1998-01-01 0.7000000000000000 1999-01-01 0.6000000000000000 2000-01-01 0.5000000000000000 2001-01-01 0.6000000000000000 2002-01-01 0.4000000000000000 2003-01-01 0.3000000000000000 2004-01-01 0.2000000000000000 2005-01-01 0.6000000000000000 2006-01-01 0.6000000000000000 2007-01-01 0.6000000000000000 2008-01-01 1.3000000000000000 2009-01-01 2.0000000000000000 2010-01-01 2.1490000000000000 2011-01-01 1.9680000000000002 2012-01-01 1.7469999999999999 2013-01-01 1.3990000000000000 2014-01-01 1.0470000000000000 2015-01-01 0.9240000000000000 2016-01-01 0.9790000000000001