Year Number 1996 68.0851058959961 1998 73.9361724853516 2000 79.8941802978516 2002 82.0105819702148 2003 82.4120635986328 2004 74.271842956543 2005 75.2427215576172 2006 71.0144958496094 2007 77.2946853637695 2008 75 2009 76.3033142089844 2010 75.8293838500977 2011 68.2464447021484 2012 69.1943130493164 2013 66.8246459960938 2014 73.3333358764648 2015 68.5714263916016 2016 70.9523773193359 2017 77.6190490722656 2018 78.7735824584961 2019 66.9811325073242 2020 66.9811325073242 2021 61.3207550048828 2022 62.7358474731445