Year Number 1996 9.8360652923584 1998 10.9289617538452 2000 10.382513999939 2002 23.2432441711426 2003 31.8918914794922 2004 25.8706474304199 2005 25 2006 23.9024391174316 2007 22.8155345916748 2008 27.1844654083252 2009 28.2296657562256 2010 28.7081336975098 2011 29.3838863372803 2012 27.962085723877 2013 26.5402851104736 2014 24.519229888916 2015 25.7142848968506 2016 27.1428565979004 2017 21.9047622680664 2018 18.5714282989502 2019 19.0476188659668 2020 28.0952377319336 2021 30.4761905670166 2022 28.7735843658447