Year	% of expense
2004	11.315357176496057
2008	10.344056439409062
2009	11.870066283937781
2010	0.23095775719378916
2011	1.93938270953603
2014	19.497157362763303
2015	17.897684197431495
2016	25.88743001861979
2017	23.42495929508668
2018	24.238254595839717
2019	16.58485300597562
2020	17.769044142301187
2021	13.22447324694949