Year Number 1996 9.04522609710693 1998 9.5 2000 9.45273590087891 2002 17.9104480743408 2003 11.4427862167358 2004 10.5769233703613 2005 7.17703342437744 2006 13.3971290588379 2007 11.9617223739624 2008 10.0961542129517 2009 16.5876770019531 2010 12.7962083816528 2011 14.0845069885254 2012 15.962441444397 2013 15.023473739624 2014 18.269229888916 2015 14.7619047164917 2016 15.7142858505249 2017 20.4761905670166 2018 19.0476188659668 2019 18.5714282989502 2020 20.4761905670166 2021 17.1428565979004 2022 16.5094337463379