Year % 2004 6.63 2005 6.63 2006 6.63 2007 6.72 2008 6.72 2009 6.72 2010 6.72 2011 6.72 2012 6.73 2013 6.73 2014 6.73 2015 6.72 2016 6.72 2017 6.74 2018 6.74 2019 6.74 2020 6.74 2021 6.74