Year number of cases 2008 29236540 2009 13686340 2010 26981100 2011 11995700 2012 19416530 2013 17057210 2014 15823253 2015 11335452 2016 17725211 2017 10544006 2018 12057633 2019 15419219 2020 16569752 2021 19100290 2022 13802960 2023 14574161