Year Number 1996 1.05037176609039 1998 1.08426582813263 2000 1.28314232826233 2002 0.903408944606781 2003 0.645857214927673 2004 0.655790030956268 2005 0.931847214698792 2006 0.912748575210571 2007 0.787657201290131 2008 0.7489093542099 2009 0.598137140274048 2010 0.856766223907471 2011 0.937754094600677 2012 0.744266331195831 2013 0.825588941574097 2014 0.361632436513901 2015 0.674569547176361 2016 0.715953171253204 2017 0.779472529888153 2018 0.673826813697815 2019 0.65869414806366 2020 0.701772809028625 2021 0.744613945484161 2022 0.756404340267181