Year % 1996 23.76 1999 19.08 2000 13.41 2001 12.19 2002 13.63 2003 13.82 2006 12.68 2007 12.59 2008 14.43 2009 15.62 2010 14.06 2011 13.03 2012 12.52 2013 12.52 2014 13.15 2015 13.15 2016 13.15 2017 14.23 2018 14.2 2019 14.25 2020 8.85