Year % 1991 15.35 1994 8.75 1995 9.72 1996 11.67 1997 11.8 1998 12.04 1999 10.78 2000 13.6 2001 13.59 2002 13.39 2003 13.44 2004 9.7 2005 8.41 2006 7.17 2007 8 2008 8.46 2009 7.95 2010 8.33 2011 8.4 2012 8.34 2013 8.24 2014 8.14 2015 8.1 2016 8.28 2017 8.11 2018 8.14 2019 8.14 2020 7.46 2021 8.11