Year % 1992 4.07 1996 15.41 1997 14.34 1998 14.38 1999 9.76 2000 11.02 2001 13.87 2002 13.3 2003 11.4 2004 10.67 2005 9.05 2006 9.81 2007 9.73 2008 0.3 2009 0.43 2010 0.54 2011 0.01 2014 0 2016 0.01 2017 0.01 2018 0.01 2019 0 2020 0 2021 0