Year % 1993 25.34 1997 15.39 2001 17.64 2002 14.89 2003 14.51 2004 18.13 2005 14.52 2006 17.28 2007 16.07 2008 11.58 2009 11.03 2010 11.19 2011 10.46 2012 11.12 2013 10.3 2015 10.64 2016 14.72 2018 10.8 2020 11.65 2021 11.66