Year	% of expense
1991	26.380448449287506
1992	41.37569981623147
1993	36.60856351121838
1994	31.963470319634702
1996	13.200767720049992
1997	8.974748039419254
1998	9.430707076024161
1999	9.832788728969406
2010	28.019190757844438
2011	29.108878794687588
2012	28.954431542422544
2013	31.079144552121935
2014	27.990921468245183
2015	36.81637595876187
2016	33.97312442357369
2017	32.03198666898573
2019	28.45054085387208
2020	32.02458757323941
2021	26.310030032615707