Year % 1996 4.59 2000 4.31 2001 4.55 2003 4.68 2004 4.76 2005 4.78 2006 3.98 2007 4.35 2008 4.11 2009 4.78 2010 4.26 2011 4.64 2012 4.21 2013 8.36 2014 4.21 2015 4.97 2016 4.94 2020 1.99 2021 2.06