Year Number 1996 9.78260898590088 1998 8.69565200805664 2000 7.60869550704956 2002 16.7567558288574 2003 18.9189186096191 2004 20.8955230712891 2005 20.5882358551025 2006 20.5882358551025 2007 22.3300971984863 2008 24.2718448638916 2009 33.9712905883789 2010 39.2344512939453 2011 40.7582931518555 2012 38.8625602722168 2013 38.8625602722168 2014 49.038459777832 2015 47.1428565979004 2016 42.3809509277344 2017 36.1904754638672 2018 43.8095245361328 2019 43.3333320617676 2020 41.4285697937012 2021 40.476188659668 2022 43.3962249755859