Year	% of expense
1990	1.0550952929375463
1991	1.1396803335649757
1992	1.3955148800830814
1993	1.3547324098370652
1994	1.1625169227146979
1995	8.650021970926634
1996	7.353524530367668
1997	8.236138288991206
1998	7.650156284610383
1999	8.228010306593116
2000	7.834863640768101
2001	7.852263744208507
2002	7.6001216105635745
2003	7.5280649839572416
2004	7.618322013249985
2005	7.831439684777898
2006	8.034401933975799
2007	8.120976515072831
2008	8.525032265539537
2009	8.21672780961318
2010	7.934365947764212
2011	8.101536444859093
2012	7.793177115989423
2013	7.988025977380282
2014	7.711256217782854
2015	7.9684343979849315
2016	8.458315906060012
2017	9.605382619113925
2018	8.400505842730194
2019	8.294225334561592
2020	8.654472926019363
2021	9.164790800350474
2022	9.491162678109287