Year Number 1996 10.1063833236694 1998 9.57446765899658 2000 6.87830686569214 2002 12.6984128952026 2003 16.0804023742676 2004 18.9320392608643 2005 20.8737869262695 2006 21.2560386657715 2007 16.425121307373 2008 15.384614944458 2009 11.8483409881592 2010 10.9004735946655 2011 14.6919431686401 2012 18.4834117889404 2013 14.2180099487305 2014 11.4285717010498 2015 10.4761905670166 2016 18.5714282989502 2017 13.3333330154419 2018 11.3207550048828 2019 10.8490562438965 2020 10.3773584365845 2021 4.71698093414307 2022 2.8301887512207