Year % 2000 4.22 2001 4.83 2002 4.27 2003 4.77 2004 4.68 2005 4.54 2006 4.19 2007 3.99 2008 3.7 2009 4.28 2010 3.84 2011 3.53 2012 3.13 2013 3.37 2014 3.46 2015 3.48 2016 3.64 2017 3.11 2018 3.04 2019 2.65 2020 2.14 2021 3.45