Year % 2001 12.38 2002 9.5 2003 9.49 2005 8.8 2006 8.39 2007 7.87 2008 7.94 2009 7.9 2010 7.91 2011 7.93 2012 7.91 2014 7.73 2016 7.07 2018 7.3 2020 7.3 2021 6.94