Year % 2000 4.54 2001 4.6 2002 4.77 2003 4.53 2004 4.26 2005 4.26 2006 4.25 2007 4.03 2008 4.03 2009 4.02 2010 4.22 2011 4.21 2012 4.2 2013 4.19 2014 4.18 2015 4.19 2016 4.13 2017 4.14 2018 4.12 2019 4.1 2020 3.96 2021 2.83