Year % 1996 21.77 1999 18.08 2000 13.98 2001 13.82 2002 13.94 2003 14.39 2006 12.54 2007 12.14 2008 12.2 2009 13.55 2010 11.93 2011 11.57 2012 10.86 2013 10.86 2014 11.43 2015 11.43 2016 11.43 2017 11.38 2018 11.44 2019 12.32 2020 9.82