Year % 2001 6.78 2004 6.1 2005 6.52 2006 6.48 2007 6.52 2008 6.33 2009 6.26 2010 6.24 2011 6.19 2012 6.2 2013 6.15 2014 6.02 2015 6.17 2016 6.24 2017 6.22 2018 6.22 2019 10.82 2020 6.12 2021 6.37