Year % 1985 14.4 1988 14.3 1992 14.6 1995 13.9 1997 14.3 2000 12.9 2003 13.9 2004 13.4 2005 13.6 2006 13.9 2007 13.6 2008 13.9 2009 13.9 2010 13.9 2011 14 2012 14.2 2013 14.1 2014 13.9 2015 14 2016 14.1 2017 14.2 2018 14.3 2019 14.2 2020 14.5 2021 14.4