Year	% of expense
1990	38.23790293126298
1991	30.720875626305766
1992	36.670551892213524
1993	31.748881381947253
1994	36.337544936672
1995	36.25891802814956
1996	28.601794682848226
1997	30.81580007476899
1998	40.88361621612991
1999	31.110561865444254
2000	25.004179031415035
2001	26.295656386588668
2002	27.77924910180199
2014	16.29971190832569
2015	17.53875402463343
2016	20.022744631475177
2017	19.0102746792443
2018	18.41146097547332
2019	16.40360686646098
2020	15.493984638066117
2021	16.438537429040746
2022	14.465389065223452