Year % 1994 13.1 1995 13.3 1996 13.4 1997 13.5 1998 12.9 1999 13.1 2000 13.4 2003 13.4 2004 13.2 2005 13.4 2006 13.3 2007 13.1 2008 13.3 2009 13 2010 13.2 2011 13.1 2012 13.3 2013 13.1 2014 13.2 2015 13.2 2016 13.2 2017 13.3 2018 13 2019 13.3 2020 13.5 2021 13.3