Year % of people at risk 2003 0.2 2004 0.3 2005 0.3 2006 0.3 2007 0.2 2008 0.2 2009 0.2 2010 0.2 2011 0.4 2012 0.7 2013 0.7 2014 0.7 2015 0.8 2016 0.5 2017 0.4 2018 0.2 2019 0.3 2020 0.3 2021 0.3 2022 0.3