Year % of profit 2005 32.5 2006 32.5 2007 32.8 2008 34.1 2009 32.5 2010 31.7 2011 31.5 2012 31.5 2013 29.9 2014 29.9 2015 29.9 2016 29.9 2017 30 2018 37 2019 41.8