Year % 1996 23.06 1999 21.75 2000 18.14 2001 21.82 2002 18.25 2003 18.04 2006 14.14 2007 13.59 2008 13.83 2010 9.56 2011 14.15 2012 13.02 2013 14.33 2015 17.68 2016 15.08 2019 16.46