Year % 1996 21.18 1997 21.18 1998 21.18 1999 21.18 2000 21.18 2001 21.18 2002 21.17 2003 21.17 2004 21.17 2005 21.17 2006 21.17 2007 21.17 2008 21.23 2009 21.23 2010 21.23 2011 21.23 2012 21.23 2014 21.21 2015 21.21 2016 21.21 2017 21.21 2018 21.24 2019 21.24 2020 21.24 2021 21.24