Year % 2005 3.61 2007 3.02 2008 2.73 2009 2.73 2011 3.13 2012 4.05 2013 4.45 2014 3.52 2015 4.29 2016 3.85 2017 16.58 2018 19.42 2019 11.79 2020 5.16 2021 5.13