Year % 1995 24.05 1998 23.77 2000 23.81 2001 23.73 2002 23 2003 23.01 2004 23.01 2005 22.81 2007 21.38 2008 21.32 2009 21.3 2010 21.17 2011 21.45 2012 20.85 2013 20.83 2015 17.74 2016 20.55 2019 20.19