Year % 1997 7.04 2001 7.04 2002 7.04 2003 7.04 2004 6.35 2005 6.35 2006 6.35 2007 5.38 2008 5.38 2009 5.38 2010 5.38 2011 5.38 2012 5.15 2013 5.15 2015 5.15 2016 5.15 2018 5.1 2020 5.1 2021 5.1