Year % 2007 9.34 2008 10.24 2009 9.55 2010 8.94 2011 8.33 2012 5.77 2013 4.73 2014 4.42 2015 4.02 2016 3.62 2017 3.63 2018 3.75 2019 3.02 2020 3.33 2021 3.94