Year % 1993 17.15 2000 16.97 2001 14.93 2002 14.93 2003 14.93 2004 14.94 2007 14.68 2008 14.68 2009 14.68 2010 15 2013 14.44 2016 13.33 2017 13.33 2018 13.31 2019 13.31 2020 13.26 2021 13.26