Year Percent 1989-01-01 104 1990-01-01 48.00 1991-01-01 36.00 1992-01-01 32.00 1993-01-01 29.00 1994-01-01 28.00 1995-01-01 25.00 1996-01-01 22.00 1997-01-01 24.50 1998-01-01 18.25 1999-01-01 19.00 2000-01-01 21.50 2001-01-01 14.00 2002-01-01 7.50 2003-01-01 5.75 2004-01-01 7.00 2005-01-01 4.75 2006-01-01 4.25 2007-01-01 5.25 2008-01-01 5.25 2009-01-01 3.75 2010-01-01 3.75 2011-01-01 4.75 2012-01-01 4.50 2013-01-01 2.75 2014-01-01 2.25 2015-01-01 1.75 2016-01-01 1.75 2017-01-01 1.75