Year % 2000 4.53362308427762 2001 4.37442379662555 2002 4.44884227131124 2003 4.72008753592587 2004 4.13111508449636 2005 4.00263570158551 2006 3.9331481037198 2007 3.93046347398182 2008 3.54498342385846 2009 3.58055704400582 2010 3.34695854756955 2011 3.39834968162577 2012 3.40190818933219 2013 3.12721632769082 2014 3.81853173622268 2015 3.15097692921519 2016 2.90217699270567 2017 3.05810269015117 2018 3.17070498621899 2019 2.87616670953053 2020 2.81978851524495