Year Number 1996 6.03015089035034 1998 7 2000 7.96019887924194 2002 5.97014904022217 2003 8.4577112197876 2004 3.36538457870483 2005 3.34928226470947 2006 1.91387557983398 2007 3.34928226470947 2008 4.32692289352417 2009 4.26540279388428 2010 4.26540279388428 2011 4.6948356628418 2012 5.63380289077759 2013 6.57277011871338 2014 6.25 2015 5.2380952835083 2016 6.1904764175415 2017 5.7142858505249 2018 6.1904764175415 2019 6.1904764175415 2020 6.1904764175415 2021 6.66666650772095 2022 6.13207530975342