Year % 1997 0 1998 0 1999 0 2000 0 2001 0 2002 0 2003 0 2004 0 2005 0 2006 0 2007 0 2008 0 2009 0 2010 0 2011 0 2012 0 2013 0 2014 0 2015 0 2016 12.5 2017 12.5 2018 12.5 2019 12.5 2020 6.25 2021 6.25 2022 6.25 2023 6.25