Year % 1996 20.82 1999 17.39 2000 9.24 2001 9.28 2002 9.27 2003 9.28 2006 9.04 2007 9.04 2008 9.04 2009 9.04 2010 8.76 2011 8.75 2012 8.95 2013 8.95 2014 8.8 2015 8.8 2016 8.81 2017 8.81 2018 8.97 2019 10.33 2020 8.7