Year % 2005 4.9390008943253 2006 4.75092644765004 2007 4.50428076628894 2008 4.19912384001137 2009 4.70300396072203 2010 4.62021662059414 2011 4.69684531050885 2012 4.75557889210946 2013 4.67249759967552 2014 4.69700335511658 2015 5.31731759650771 2016 5.44397257111967 2017 5.91271906081673 2018 5.91854176977054 2019 6.19862631822147 2020 6.37432250408069 2021 6.16933763669525 2022 5.8647335037465