Year % 1996 26.35 1999 26.06 2000 26.02 2001 26.94 2002 26.61 2003 26.47 2004 23.63 2006 21.23 2007 22.6 2010 15.42 2011 15.39 2012 15.97 2013 22.83 2020 21.71 2021 21.69