Year % 1996 17.85 1999 16.67 2000 9.85 2001 9.53 2002 9.83 2003 10.08 2004 9.43 2006 8.91 2007 8.92 2010 7.45 2011 7.34 2012 10.38 2013 9.59 2015 10.52 2016 10.84 2020 8.41 2021 8.61