Year Number 1996 9.04255294799805 1998 21.8085098266602 2000 14.8148145675659 2002 14.2857141494751 2003 9.54773902893066 2004 11.1650485992432 2005 12.62135887146 2006 12.5603866577148 2007 11.5942029953003 2008 13.4615383148193 2009 14.6919431686401 2010 16.5876770019531 2011 15.6398105621338 2012 18.4834117889404 2013 26.0663509368896 2014 30.9523811340332 2015 28.5714282989502 2016 30.4761905670166 2017 30 2018 30.1886787414551 2019 23.5849056243896 2020 23.1132068634033 2021 23.5849056243896 2022 23.1132068634033