Year % 1995 4.63 1996 4.23 1997 4.26 1998 4.3 2000 3.86 2001 3.91 2002 3.83 2003 3.83 2004 3.76 2005 16.36 2006 12.78 2007 12.84 2008 12.82 2009 12.74 2010 12.75 2011 12.74 2012 13.37 2013 13.34 2014 13.34 2015 13.48 2016 13.28 2017 13.24 2018 13.23 2019 13.23 2020 13.23 2021 13.23