Year % 1990 56.36 1992 27.01 1996 23.72 1997 20.14 1999 28.54 2000 23.36 2001 26.65 2002 23.08 2003 21.45 2004 22.97 2005 14.06 2006 8.99 2007 11.99 2008 6.13 2009 7.04 2010 7.34 2011 7.33 2012 6.32 2013 6.34 2015 7.49 2016 7.57 2017 6.85 2018 6 2019 8.77 2020 7.65 2021 7.31