Year	% of revenue
1990	21.960247510231447
1991	27.524267036450077
1992	29.98210731300705
1993	33.87928717041152
1994	33.39614012622336
1995	36.482069390450455
1996	39.25377423881253
1997	40.74145675212216
1998	41.78904135571459
1999	42.111980425326244
2000	43.86411636674087
2001	43.8253146297782
2002	37.4458707258889
2003	34.251352024359164
2004	37.16692016306156
2005	37.23322264879387
2006	35.89168929946959
2007	33.92856589274654
2008	31.676974570379418
2009	29.458708366487812
2010	28.603677016808977
2011	29.65388704018655
2012	29.57419683515513
2013	29.165483137407332
2014	27.594534359742372
2015	28.0000349566416
2016	27.241611508650294
2017	30.25226550884887
2018	33.348220108620765
2019	29.871003229116628
2020	31.578521133679605
2021	29.543411618636835
2022	29.185881433304456