Year Number 1996 2.12765955924988 1998 0 2000 17.4603176116943 2002 12.6984128952026 2003 19.0954780578613 2004 18.9320392608643 2005 16.5048542022705 2006 16.425121307373 2007 16.9082126617432 2008 12.5 2009 14.2180099487305 2010 12.3222751617432 2011 11.3744077682495 2012 7.5829381942749 2013 8.05687236785889 2014 11.9047622680664 2015 17.619047164917 2016 17.1428565979004 2017 16.1904754638672 2018 12.7358493804932 2019 13.6792449951172 2020 12.2641506195068 2021 20.2830181121826 2022 16.9811325073242