Year	% of expense
2008	7.1852781894218225
2009	6.291530328978093
2010	6.192334990460758
2011	5.393193557275785
2012	5.806740639925272
2013	5.942090195200661
2014	6.231650289009437
2015	7.000829835416511
2016	7.738832121527701
2017	8.260765748979283
2018	9.836477192742901
2019	9.014649673675194
2020	8.480182723175723
2021	9.500352151665938