Year % 1993 18.12 1995 16.63 1997 13.31 1998 13.27 1999 13.27 2000 13.28 2001 11.73 2002 10.25 2003 9.7 2004 10.25 2005 9.67 2006 9.72 2007 9.72 2008 5.5 2009 5.5 2010 5.48 2011 3.88 2013 3.56 2014 3.56 2015 2.75 2017 2.78 2018 2.78 2019 2.78 2020 2.78 2021 2.78