Year % 2001 12.974694274941323 2002 17.635633934815303 2003 19.03071210564593 2004 18.574989317214385 2005 20.45039514770497 2006 15.008831274494286 2007 11.109732280862818 2008 12.867198573235761 2009 11.551645248052909 2010 9.448941172939685 2011 8.051209846006026 2012 7.800020677105388 2013 7.215107708836655 2014 7.487811197208108 2015 7.295768868083527 2016 7.0353902286288115 2017 6.74277629948987 2018 7.137017817551154 2019 6.240646024148836 2020 7.442484806682685 2021 7.456818535820879 2022 6.929498995387845 2023 7.151194253672573