Year Number 2002 10.8108110427856 2003 9.72972965240479 2004 12.93532371521 2005 12.2549018859863 2006 4.41176462173462 2007 3.39805817604065 2008 6.7961163520813 2009 11.9617223739624 2010 13.3971290588379 2011 14.6919431686401 2012 16.1137447357178 2013 17.5355453491211 2014 18.75 2015 14.7619047164917 2016 13.3333330154419 2017 24.761905670166 2018 22.380952835083 2019 21.4285717010498 2020 24.761905670166 2021 23.3333339691162 2022 33.9622650146484