Year	% of revenue
1991	25.98357111975786
1992	16.486763928204862
1993	15.868199560868495
1994	21.124102680815128
1995	26.850794217383545
1996	24.767252844687455
1997	24.50708400023712
1998	27.832059436634776
1999	27.426304450633175
2000	22.145880820579617
2001	21.409544950055494
2002	21.764749646603676
2003	22.996295203435952
2004	22.690458634419702
2005	20.947455855952413
2006	20.291909746053534
2007	21.002106002106004
2008	22.078939179143184
2009	18.010963060003792
2010	17.40050576609215
2011	17.511834467992575
2012	18.212703101920237
2013	19.958382352941175
2014	20.458532805711595
2015	20.8544135397874
2016	20.333887105437377
2017	19.72306485657274
2018	20.469328636156238
2019	19.809639372906858
2020	20.652524220331323
2021	22.59302255587373
2022	21.773810064664637