Year % 1987 10.6 1990 10.3 1992 11 1994 10.6 1996 11 1998 10.9 2000 11.8 2003 12.2 2006 12.9 2009 12.9 2011 12.9 2013 12.9 2015 13.3 2017 13.3 2020 13 2022 14