Year % 2001 15.03 2002 15.03 2003 13.59 2004 13.78 2005 13.56 2006 13.29 2007 13.48 2008 13.23 2009 12.97 2010 12.86 2011 12.78 2012 13.02 2013 13.43 2014 12.99 2017 13.37 2018 13.23 2019 11.74 2020 12.5 2021 12.57