Year % 2001 9.56 2002 9.02 2004 8.56 2005 8.54 2006 8.5 2007 8.25 2008 8.24 2009 8.23 2010 8.13 2011 8.13 2012 8.1 2013 8.11 2014 8.11 2015 8.12 2016 8.19 2017 8.4 2018 8.48 2019 10 2020 8.43 2021 8.44