Year % 2007 8.48 2008 8.48 2009 8.48 2010 8.49 2011 8.48 2012 8.57 2013 8.31 2014 8.56 2015 8.31 2016 8.31 2017 8.33 2018 8.33 2019 8.33 2020 8.33 2021 8.33