Year Number 1996 12.9032258987427 1998 11.2299461364746 2000 12.2340421676636 2002 19.5767192840576 2003 18.518518447876 2004 13.7931032180786 2005 9.7560977935791 2006 17.0731716156006 2007 15.5339803695679 2008 14.5631065368652 2009 5.26315784454346 2010 4.2857141494751 2011 2.84360194206238 2012 4.26540279388428 2013 8.05687236785889 2014 9.61538505554199 2015 8.5714282989502 2016 10.9523811340332 2017 11.9047622680664 2018 12.8571424484253 2019 15.2380952835083 2020 15.7142858505249 2021 22.380952835083 2022 24.5283012390137