Year % 2007 7.64 2008 7.63 2009 7.63 2010 7.63 2011 7.53 2012 7.53 2013 7.53 2014 7.52 2015 7.5 2016 7.5 2017 7.5 2018 7.5 2019 7.5 2020 7.5 2021 7.62