Year % 1996 19.15 1999 17.63 2000 15.37 2001 13.22 2002 13.22 2003 11.07 2004 10.59 2005 10.71 2006 11.93 2007 13.08 2008 12.57 2009 16.29 2010 9.28 2011 9.28 2012 10.48 2013 14.81 2014 7.08 2015 9.53 2016 9.48 2017 13.38 2018 13.58 2019 13.9 2020 13.9 2021 13.9