Year % 2003 4.99 2005 4.92 2006 4.86 2007 4.7 2008 4.7 2009 4.7 2011 4.7 2012 4.63 2013 4.63 2014 4.62 2015 4.63 2016 4.63 2017 4.64 2018 4.64 2019 4.66 2020 4.64 2021 4.64