Year % 1996 15.45 1997 15.72 1999 15.65 2000 14.18 2001 14.19 2002 14.13 2003 14.43 2004 14.44 2005 14.46 2006 14.11 2007 13.87 2008 13.87 2009 13.84 2010 13.41 2011 13.48 2012 12.88 2013 12.55 2014 12.55 2015 11.33 2016 11.62 2017 12.68 2018 12.35 2019 11.26 2020 11.26 2021 10.92