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 15.85 2007 16.83 2008 16.67 2009 16.29 2010 9.28 2011 9.28 2012 12.67 2013 19.16 2014 9.02 2015 12.52 2016 12.26 2017 18.29 2018 18.72 2019 17.92 2020 17.92 2021 17.92