Year % 2001 3.64 2006 8.54 2007 8.01 2008 8.03 2009 7.79 2010 7.95 2011 7.8 2012 7.11 2013 6.82 2014 6.78 2015 6.82 2016 6.53 2017 6.51 2018 6.79 2019 18.92 2020 6.6 2021 6.63