Year % of expense 2005 24.96930707656043 2006 23.973071169053217 2007 24.77145351542135 2008 23.123883647719033 2009 23.181956212448306 2010 22.404911748613703 2011 22.085682020082707 2012 22.628342459017794 2013 25.67358694117083 2014 21.61155396255736 2015 22.246781812707304 2016 28.91290085408614 2017 23.938782788249714 2018 29.255495661571008 2019 40.57558147998567 2020 29.506815175207322 2021 24.25085442221858 2022 26.571455489671774