Year	% of expense
2009	18.84187260999654
2010	23.14086101455864
2011	25.438093586144987
2012	27.048888409238074
2013	25.553089342069
2014	26.621075996991767
2015	33.12170707180498
2016	32.30072738259482
2017	30.64971766759537
2018	30.693665866646025
2019	32.839593863737996
2020	32.55227031173175
2021	32.247911498916146
2022	32.458978744306364