Year % 1992 15.09 1995 12.78 1997 12.66 1998 12.76 1999 12.66 2000 12.68 2001 12.71 2002 12.71 2003 12.7 2004 12.65 2005 12.64 2006 12.77 2007 13.58 2008 13.8 2009 13.8 2010 12.99 2011 13.8 2012 13.8 2013 13.8 2014 13.38 2015 12.49 2016 11.74 2017 10.46 2018 10.46 2019 10.46 2020 10.46 2021 10.46