Year % 2004 8.7 2005 8.7 2006 9.3 2007 9.5 2008 9.2 2009 8.6 2010 8.5 2011 8.7 2012 8.6 2013 8.3 2014 8.4 2015 8.5 2016 8.7 2017 9.4 2018 8.8 2019 9.5 2020 9.1 2021 9.1