Year	% of expense
1983	8.327268316351285
1984	9.251164663254155
1985	9.681488489435509
1986	9.62751427861932
1987	9.799221516064478
1988	10.311318421145623
1989	12.67727617191729
1990	10.525401069518717
1991	14.564755745266147
1992	12.285948123898262
1993	14.127045407299619
1994	12.708793268629984
1995	14.478382814483911
1996	13.73324700394583
1997	13.936045710309692
1998	13.203488391035947
1999	14.882777579121404
2000	14.768773125917031
2001	14.193604308367197
2002	13.439913714228977
2003	13.16723696722341
2004	11.977140614217591
2005	11.99958934639567
2006	12.230245576794317
2007	11.854101391956444
2008	11.214105557603741
2009	11.341809919667087
2010	14.721874829209295
2011	13.22773378576218
2012	13.472157583068519
2013	11.405970673526685
2014	13.245808326009975
2015	12.614138499251752
2016	12.670848406661351
2017	12.82380928580852
2018	13.784053896546101
2019	13.369937371377645
2020	12.078141153063749
2021	9.42693993148321
2022	10.382575649712727