Year % 1990 27.06 1993 23.2 1994 23.2 1997 18.64 1998 9.26 2000 8.08 2001 8.07 2003 7.68 2004 8.55 2005 9.85 2006 9.65 2007 9.52 2008 9.41 2009 9.47 2010 8.13 2011 8.02 2012 7.72 2014 7.32 2015 6.6 2017 6.92 2018 7.67 2019 7.67 2020 6.43 2021 4.12