Year % 1993 14.82 1997 21.4 1998 20.71 2000 17.72 2003 15.06 2005 12.21 2006 11.98 2007 12.08 2008 12.53 2009 12.45 2010 12.49 2011 12.3 2012 12.53 2013 12.52 2014 12.43 2015 11.32 2016 11.59 2018 11.68 2019 11.69 2020 11.67 2021 11.41