Year % 2001 12.1 2002 9.23 2003 9.15 2005 8.44 2006 7.74 2007 7.53 2008 7.94 2009 4.45 2010 4.42 2011 7.93 2012 4.42 2014 4.12 2016 3.48 2018 4.42 2020 4.36 2021 4.38