Year Percent 1990-01-01 12.58 1991-01-01 8.50 1992-01-01 5.75 1993-01-01 4.75 1994-01-01 7.05 1995-01-01 7.50 1996-01-01 6.18 1997-01-01 5.00 1998-01-01 4.76 1999-01-01 5.00 2000-01-01 6.25 2001-01-01 4.28 2002-01-01 4.75 2003-01-01 5.23 2004-01-01 5.25 2005-01-01 5.50 2006-01-01 6.25 2007-01-01 6.75 2008-01-01 4.35 2009-01-01 3.74 2010-01-01 4.75 2011-01-01 4.30 2012-01-01 3.03 2013-01-01 2.50 2014-01-01 2.50 2015-01-01 2.00 2016-01-01 1.50 2017-01-01 1.50