Year % 2002 4.01 2003 4.93 2004 4.93 2005 4.93 2006 4.94 2007 4.37 2008 4.27 2009 4.41 2010 4.32 2011 4.32 2012 4.11 2013 4.29 2014 4.3 2015 4.4 2016 4.4 2017 3.97 2018 3.64 2019 3.53 2020 4.05 2021 4.12