Year % of people at risk 2003 0.5 2004 0.4 2005 0.3 2008 0.6 2009 0.2 2010 0.5 2011 0.3 2012 0.3 2013 0.3 2014 0.3 2015 0.3 2016 0.2 2017 0.3 2018 0.2 2019 0.1 2020 0.1 2021 0.1