Year % 1993 18.68 1998 18.12 1999 13.33 2000 13.64 2002 13.9 2003 14.01 2004 14.07 2005 14.09 2006 12.5 2007 12.57 2008 14.09 2009 12.3 2010 12.22 2011 12.17 2012 12.05 2013 12.19 2014 12.23 2015 12.23 2016 11.97 2018 12.12 2019 13.55 2020 12.19 2021 12.25