Year % 1992 13.73 1993 13.58 1995 12.16 1996 14.42 1997 14.92 1998 16.49 1999 15.42 2000 15.31 2001 14.29 2002 13.12 2003 14.05 2004 13.18 2005 12.83 2006 13.02 2007 13.5 2008 11.79 2009 13.49 2010 14.09 2011 14.3 2012 14.14 2013 13.27 2014 13.84 2015 13.25 2016 13.74 2017 16.58 2018 13.87 2019 12.66 2020 12.16 2021 11.46