Year % 2007 4.28 2008 2.63 2009 2.72 2010 2.74 2011 2.91 2012 2.51 2013 1.72 2014 1.69 2015 1.65 2016 1.2 2017 1.21 2018 1.15 2019 0.68 2020 1.2 2021 1.22