Year % 2008 0.723251027713466 2009 1.27871052608886 2010 1.51981365217834 2011 1.68434907314772 2012 1.51215755076448 2013 1.33872670729875 2014 1.13088790719266 2015 1.0533756114736 2016 1.18473037859688 2017 1.00040357973015 2018 0.746427849824663 2019 0.801131694159603 2020 0.736074194281787 2021 0.525489505428339