Year Number 1996 19.0954780578613 1998 24.5 2000 24.8756217956543 2002 11.4427862167358 2003 11.4427862167358 2004 13.4615383148193 2005 13.8755979537964 2006 23.9234447479248 2007 22.9665069580078 2008 23.5576915740967 2009 18.0094795227051 2010 18.9573459625244 2011 16.9014091491699 2012 19.2488269805908 2013 19.2488269805908 2014 20.6730766296387 2015 25.7142848968506 2016 23.3333339691162 2017 28.5714282989502 2018 26.6666660308838 2019 24.761905670166 2020 29.5238094329834 2021 29.0476188659668 2022 25.4716987609863