Year	% of expense
1980	4.710346104016279
1981	4.93694247923717
1982	4.931917388754987
1983	5.111213553071337
1984	5.92219247125531
1985	5.123838256045932
1986	5.274029193059781
1987	5.148759232352457
1988	4.135239331642455
1989	4.043827841715272
1990	67.43322064123045
1991	67.68241834607358
1992	67.19890955116338
1993	66.90669433087194
1994	67.39655070928248
1995	56.6346850460385
1996	57.33117993059549
1997	56.875198668042756
1998	57.952970818722136
1999	57.94796926800721
2000	58.230542062520875
2001	58.77879681822938
2002	59.30912358816087
2003	59.95598772014337
2004	59.90085660461997
2005	59.90528522760934
2006	60.39601184967056
2007	60.60160691217812
2008	60.641922558234896
2009	62.11309105044889
2010	63.27272535876819
2011	62.26514314221242
2012	62.950224476799164
2013	63.435900657454326
2014	64.21416248197444
2015	64.33671288472529
2016	64.18937614980781
2017	63.15631478291337
2018	64.2015426173835
2019	64.9710946809783
2020	66.02350049421587
2021	65.0687747990193
2022	63.48520348589943