Year % 1996 17.25 1997 17.24 1999 17.24 2000 17.24 2001 17.24 2002 17.13 2003 17.13 2004 17.13 2005 17.13 2006 17.13 2007 17.07 2008 17.07 2009 17.07 2010 17.07 2011 17.07 2012 17.12 2013 17.12 2014 17.12 2015 17.12 2016 17.12 2017 17.15 2018 17.15 2019 17.15 2020 17.15 2021 17.15