Year % 2001 16.54 2002 16.54 2003 16.04 2004 16.31 2005 16.17 2006 12.34 2007 16.38 2008 14.49 2009 14.65 2010 14.92 2011 15.02 2012 15.27 2013 16.59 2014 15.53 2017 19.24 2018 18.66 2019 16.64 2020 16.82 2021 16.74