Year % of profit 2005 35.2 2006 35.2 2007 35.2 2008 34.8 2009 34.8 2010 35.2 2011 34.4 2012 34.4 2013 33.5 2014 32.8 2015 32.8 2016 32.5 2017 32.5 2018 32.3 2019 34.4