Year % of expense 2002 17.861019100584677 2003 17.1424078005819 2004 11.1336900145932 2005 11.223259444065743 2006 10.23988820743731 2007 9.535541855811893 2008 9.462810032459121 2009 7.650930152312736 2010 7.480572738040231 2011 5.838194550155896 2012 6.5266125417240834 2013 8.79267621895649 2014 7.432080386350806 2015 8.172478172923627 2016 9.225682454420333 2017 9.149938357277593 2018 11.314004108316764 2019 10.519376102409094 2020 9.970574598864788 2021 10.22511123696571