Year Number 1996 38.2513656616211 1998 22.4043712615967 2000 20.7650279998779 2002 25.9459457397461 2003 21.6216220855713 2004 20.8955230712891 2005 24.0196075439453 2006 18.536584854126 2007 20.8737869262695 2008 20.3883495330811 2009 20.5741634368896 2010 19.6172256469727 2011 17.5355453491211 2012 18.9573459625244 2013 20.3791465759277 2014 15.384614944458 2015 12.380952835083 2016 10 2017 9.0476188659668 2018 9.0476188659668 2019 10 2020 11.9047622680664 2021 12.380952835083 2022 12.7358493804932