Year	% of expense
1990	59.759713342232835
1991	55.63130839738341
1992	63.30713607370129
1993	67.95747439848657
1994	68.42906523881274
1995	66.6754114416636
1996	66.48583819930705
1997	64.59012292332359
1998	64.21342738648045
1999	62.020719494778
2000	60.670530960687465
2001	58.87414883295114
2002	43.432850623263406
2003	44.554503559376954
2004	50.097232785138914
2014	66.10698075633415
2015	65.48360029614658
2016	63.7680407913133
2017	64.40332346766756
2018	66.20759763418819
2019	64.13479904080421
2020	75.298681935662
2021	73.85281254328353
2022	73.0910998618659