Year Number 1996 23.9361705780029 1998 18.0851058959961 2000 15.3439149856567 2002 20.1058197021484 2003 26.6331653594971 2004 29.1262130737305 2005 33.980583190918 2006 31.4009666442871 2007 25.1207733154297 2008 24.0384616851807 2009 19.9052124023438 2010 20.8530807495117 2011 25.5924167633057 2012 27.488151550293 2013 21.3270149230957 2014 20.9523811340332 2015 19.5238094329834 2016 28.0952377319336 2017 20.4761905670166 2018 15.0943393707275 2019 14.6226415634155 2020 12.7358493804932 2021 6.60377359390259 2022 6.60377359390259