Year % 2001 18.26 2002 18.35 2003 17.53 2005 16.3 2006 15.7 2007 14.64 2008 13.77 2010 14.06 2011 14.22 2012 14.94 2014 9.89 2016 15.13 2020 9.05 2021 8.13