Year per 1,000 population at risk 2000 6.64376884661751 2001 2.905047933838 2002 2.10569531701573 2003 1.81606876084208 2004 1.84287521445709 2005 1.75245764894015 2006 0.810277682963393 2007 0.34795416327055 2008 0.192798949255716 2009 0.15202350771795 2010 0.169996574840701 2011 0.223924293319025 2012 0.294708771580728 2013 0.273163513896706 2014 0.264659016325032 2015 0.520678664767735 2016 1.41271023024171 2017 2.43140819671786 2018 3.48539352458216 2019 2.85066145679595 2020 5.46139255165565 2021 4.88631038529645 2022 3.33628583727037