Year % 2001 14.23 2002 12.29 2003 12.68 2005 12.51 2006 11.78 2007 10.53 2008 10.39 2009 8.64 2010 8.63 2011 10.35 2012 8.63 2014 7.1 2016 6.78 2018 8.76 2020 8.75 2021 8.56