Year % 2004 12.3 2005 11.3 2006 11.7 2007 11 2008 11.3 2009 12.3 2010 12.3 2011 12.1 2012 12.2 2013 12.2 2014 12.3 2015 12.3 2016 12.1 2017 11.7 2018 11.9 2019 12.2 2020 11.7 2021 12.1