Year	% of expense
1997	11.902683043715165
1998	14.076246334310852
1999	12.586439534491484
2000	12.250457410042692
2003	11.942526460044915
2004	11.5613262515453
2006	7.215986579942537
2007	4.96975059171643
2008	5.423032791835255
2009	5.4857413762228
2010	5.384396066335939
2011	6.075672980265446
2012	6.018928171224562
2013	5.84209806413713
2014	7.383734283864669
2015	7.299991742943187
2016	7.709051677110263
2017	8.195764876588928
2018	9.424207176075342
2019	8.948125685752123
2020	8.2500499659469
2021	7.865486076359657
2022	9.943267973681543