Year % 2001 13.8 2002 8.77 2005 6.64 2007 6.64 2008 6.58 2009 6.55 2010 6.56 2011 6.56 2013 6.54 2015 6.54 2016 6.55 2017 6.55 2018 6.55 2021 6.55