Year % 2003 11.9 2004 12.8 2005 12.7 2006 12.6 2007 13 2008 13 2009 13.2 2010 13.3 2011 13 2012 12.9 2013 12.2 2014 12.3 2015 12.5 2016 12.7 2017 12.8 2018 12.8 2019 12.9 2020 13 2021 12.3