Year % 1989 29.68 1990 20.73 1991 15.24 1992 20.66 1993 7.87 1994 7.39 1995 8.63 1996 8.73 1997 8.68 1998 11.46 1999 11.44 2000 11.35 2001 10.93 2002 10.02 2003 9.98 2004 9.98 2005 8.6 2006 8.57 2007 8.65 2008 8.69 2009 8.72 2010 8.72 2011 8.74 2012 8.73 2013 8.85 2014 8.87 2015 8.9 2016 8.9 2017 8.87 2018 8.87 2019 8.86 2020 8.86 2021 8.86