Year	% of expense
1990	4.6540347695354916
1991	4.379992584852877
1992	4.128235319770611
1993	4.178028205018959
1994	4.20286464702317
1995	3.9676267115554373
1996	4.710848327443254
1997	4.465097648638115
1998	4.917047874022388
1999	5.096296296296296
2000	5.155110807192596
2001	5.210736199183765
2002	5.228916674050825
2003	4.873587189932927
2004	5.033712737127372
2005	4.844877871663622
2006	4.676414265084448
2007	4.91527007081068
2008	5.3377514324673765
2009	5.4596944596337025
2010	5.1566234746509
2011	5.151969685008289
2012	5.110893805005608
2013	4.808044381948141
2014	4.626165939291696
2015	4.650655986335458
2016	4.621938833088817
2017	4.60155905904578
2018	4.552003406798807
2019	4.773124971651066
2020	4.256056944976412
2021	4.495181605617312
2022	5.560370588879643