Year % 1995 3.98 1996 4.19 1997 4.19 1998 4.19 1999 4.19 2000 4.21 2001 4.21 2002 4.23 2003 4.23 2004 4.24 2005 4.24 2006 4.24 2007 4.2 2008 4.19 2009 4.19 2010 4.19 2011 4.19 2012 4.17 2013 4.15 2014 4.15 2015 3.99 2016 3.99 2017 4 2018 4 2019 4 2020 4 2021 4