Year % 2003 13.6 2004 12.8 2005 11.5 2006 11.5 2007 12.2 2008 11.9 2009 12.2 2010 11.9 2011 11.7 2012 13.6 2013 14.4 2014 14.2 2015 13.2 2016 12.5 2017 11 2018 11.5 2019 11.2 2020 12.3 2021 10.5