Year % 2002 4.01 2003 4.93 2004 4.93 2005 4.31 2006 4.3 2007 3.82 2008 3.7 2009 4.25 2010 4.32 2011 4.32 2012 4.05 2013 4.23 2014 3.74 2015 3.69 2016 3.69 2017 3.54 2018 3.28 2019 3.2 2020 3.77 2021 3.76