Year % 2001 13.98 2004 17.4 2005 17.46 2006 16.41 2007 13.94 2008 12.47 2009 11.82 2010 10.84 2011 13.85 2012 13.97 2013 12.57 2014 13.04 2015 13.54 2016 12.99 2017 12.14 2018 12.69 2019 12.86 2020 12.7 2021 12.71