Year % 2001 13.454692429801892 2002 13.40520952647624 2003 13.810493084416239 2004 15.952051572726731 2005 14.382801944057919 2006 14.924543711915943 2007 15.164313432804327 2008 13.990700457786328 2009 17.623309507850486 2010 17.671256390291592 2011 15.686186065711157 2012 17.28274254160725 2013 17.9952886789035 2014 16.975110568663794 2015 18.54060054885867 2016 18.940802401153405 2017 19.069299497800145 2018 17.924169844953603 2019 18.367756050294666 2020 19.569677121609136 2021 20.786989215958307 2022 19.90788690322546 2023 19.15145466901324