Year % 1990 14.5 1992 12.5 1997 11.1 1999 11.7 2000 10.7 2001 11.6 2002 11 2004 11.4 2005 10.8 2006 11.3 2007 11.8 2008 13.1 2009 13.9 2011 14.3 2012 14.5 2013 14 2014 13.8 2015 14.2 2016 14.7 2017 14.8 2018 15.2 2019 15 2020 14.5 2021 15.3