Year % 1996 13.32 1997 18.97 1998 13.32 1999 13.32 2000 22.99 2001 13.41 2002 13.03 2003 13.15 2004 13.07 2005 12.89 2006 12.39 2007 10.26 2008 11.71 2010 10.68 2011 12.73 2012 12.77 2013 12.65 2015 11.14 2016 10.12 2017 9.24 2018 9.24 2020 8.85 2021 7.8