Year % 1995 15.81 1996 15.74 1997 15.74 1998 15.74 1999 15.74 2000 15.74 2001 15.74 2002 17.04 2003 16.94 2004 16.64 2005 16.64 2006 16.67 2007 16.92 2008 16.86 2009 16.82 2010 16.81 2011 16.81 2012 18.22 2013 18.23 2014 18.23 2015 16.48 2016 16.48 2017 16.55 2018 16.55 2020 16.55 2021 16.55