Year % 1996 15.36 1997 16.12 1999 16.92 2000 10.64 2001 10.46 2002 10.12 2003 10.07 2004 10.07 2005 9.74 2006 9.57 2007 9.51 2008 9.51 2009 10.03 2010 9.69 2011 9.98 2012 9.11 2013 9.09 2014 9.09 2015 10.62 2016 9.58 2017 14.4 2018 14.04 2019 13.51 2020 13.51 2021 11.62