Year Number 1996 13.043478012085 1998 13.043478012085 2000 12.5 2002 12.972972869873 2003 18.9189186096191 2004 14.9253730773926 2005 22.0588226318359 2006 19.6078433990479 2007 16.5048542022705 2008 17.9611644744873 2009 16.7464122772217 2010 14.3540668487549 2011 18.0094795227051 2012 21.8009471893311 2013 22.748815536499 2014 12.5 2015 13.3333330154419 2016 12.380952835083 2017 14.7619047164917 2018 11.4285717010498 2019 10.9523811340332 2020 10.4761905670166 2021 11.4285717010498 2022 10.3773584365845