Year	% of expense
1986	3.251217978940751
1987	3.6009905855825473
1988	2.8685845047401113
1989	2.9235095708617598
1990	51.42463771497911
1991	51.26485719354267
1992	56.45740635302222
1993	59.02051152879988
1994	60.58315406255171
1995	61.428471252717266
1996	61.85157207781754
1997	62.541186656725756
1998	63.22347172124384
1999	64.14401807681499
2000	64.84512744607214
2001	59.25380625537476
2002	60.421531786660445
2003	60.203693036854574
2004	59.5203833935538
2005	58.87344425330425
2006	59.1589093010646
2007	58.9467416861896
2008	56.65531390201147
2009	61.05093803777558
2010	62.7304436207548
2011	62.14080554977499
2012	62.38716038509109
2013	63.967618882812936
2014	64.59303305766524
2015	65.90283947499228
2016	66.08438233474833
2017	65.84674429419948
2018	65.27333461150944
2019	65.11075004250473
2020	70.97223492256833
2021	66.29040846070953
2022	67.69014298961312