Year	% of revenue
1991	24.519230769230713
1992	37.58382738847308
1993	43.50747901760392
1994	43.81862461139866
1995	30.53762493137152
1996	33.21097290042996
1997	29.68533857905557
1998	35.37401430450581
1999	38.677068670312934
2000	42.49061087653037
2001	42.62705273323832
2002	46.709615215007396
2003	45.67629503317464
2004	45.97450395015064
2005	46.03952979506602
2006	47.85385460402479
2007	44.94494707853513
2008	44.52847654876662
2009	44.745930173038104
2010	47.19310891244552
2011	46.080097650308666
2012	48.54530782912533
2013	49.44717689047071
2014	48.31492752472037
2015	48.26137961060536
2016	47.660143216189276
2017	48.036745607893835
2018	49.84936372857936
2019	48.669380928656295
2020	45.69091823818762
2021	46.266386365781145
2022	46.25941926837671