Year % 1991 21.46 1992 22.04 1996 14.25 1999 26.87 2001 13.78 2002 12.4 2003 12.4 2004 14.29 2005 14.13 2006 13.94 2007 14.9 2008 14.69 2010 15.81 2011 15.8 2012 16.45 2013 16.35 2021 17.73