Year Number 1996 21.5053768157959 1998 25.6684494018555 2000 29.7872333526611 2002 25.9259262084961 2003 41.798942565918 2004 35.9605903625488 2005 38.5365867614746 2006 42.926830291748 2007 38.8349533081055 2008 41.262134552002 2009 50.2392349243164 2010 49.523811340332 2011 51.1848335266113 2012 42.6540298461914 2013 45.497631072998 2014 43.269229888916 2015 41.4285697937012 2016 33.3333320617676 2017 37.1428565979004 2018 32.3809509277344 2019 33.8095245361328 2020 30.9523811340332 2021 32.8571434020996 2022 27.8301887512207