Year	% of expense
1978	1.6339869281045754
1979	0.20920502092050208
1980	1.017293997965412
1981	0.3144654088050315
1982	0.040016006402561026
1985	0.49664762850757393
1986	3.993337981253389
1987	1.015713081368775
1988	0.5882352941176471
1989	4.191514738456296
1990	28.872531046995892
1991	39.285714285714285
1992	41.827608554763444
1993	37.937211275572736
1994	38.68253237788443
1995	32.851740291331325
1996	33.62614453714637
1997	35.93167557157058
1998	33.34568951105878
1999	37.5008673184496
2000	37.01478090176427
2001	37.90427685119008
2002	41.743985621473506
2003	41.96857894013441
2004	43.91207403174153
2005	44.962859053402426
2006	46.24882880265393
2007	48.93562530570746
2008	48.756717443741806
2009	45.956673390481825
2010	46.60492153007975
2011	48.512817881690545
2012	49.98759029403179
2013	47.952631085508216
2014	45.65704252309465
2015	43.17233872655075
2016	44.04729311798912
2017	45.886248956417305
2018	46.51326533058602
2019	47.06526462054319
2020	45.03581973150541
2021	45.09193849566016