Year % 1991 14.95 1994 7.44 1995 8.4 1996 9.08 1997 8.89 1998 8.82 1999 11.57 2000 11.17 2001 10.24 2002 9.94 2003 9.84 2004 9.96 2005 8.48 2006 8.33 2007 8.46 2008 8.59 2009 8.59 2010 8.61 2011 8.62 2012 8.62 2013 8.71 2014 8.71 2015 8.71 2016 8.71 2017 8.7 2018 8.7 2019 8.7 2020 8.7 2021 8.7