Year	% of expense
2004	7.3187336483597285
2008	5.952355376629086
2009	7.149603634794421
2010	6.903738547837294
2011	8.134252574496532
2012	6.731098242066469
2013	7.145896347077981
2014	5.856595761551399
2015	6.847809657669584
2016	6.871727265878876
2017	6.622209847133982
2018	5.614778377097389
2019	6.424657514684687
2020	6.32617664660773
2021	7.3685803612678145