Year Number 1996 64.4808731079102 1998 66.6666641235352 2000 77.5956268310547 2002 72.9729766845703 2003 72.4324340820313 2004 75.6218872070313 2005 75 2006 77.5609741210938 2007 77.1844635009766 2008 78.6407775878906 2009 77.9904327392578 2010 78.4689025878906 2011 75.3554534912109 2012 80.0947875976563 2013 78.6729888916016 2014 79.8076934814453 2015 74.2857131958008 2016 74.2857131958008 2017 77.1428604125977 2018 76.1904754638672 2019 76.1904754638672 2020 75.7142868041992 2021 77.6190490722656 2022 78.7735824584961