Year	% of revenue
1991	28.116825787862933
1992	33.747714022008786
1993	32.844874103920475
1994	32.087795031622846
1995	30.541064352998113
1996	32.11088225406154
1997	31.87736008187313
1998	32.522438005791926
1999	34.88103035450256
2000	34.90943001882687
2001	34.84112702764091
2002	35.086052652840024
2003	33.550617871497074
2004	31.535168195718654
2005	33.165209569180995
2006	32.795306977322895
2007	31.348720054119173
2008	33.13146156771896
2009	33.65374069464649
2010	34.19714116613161
2011	33.66104471786508
2012	32.709354625218864
2013	31.481222622821104
2014	31.645124739738083
2015	30.62775567052928
2016	33.07612344446266
2017	32.45023094169769
2018	38.064810780743024
2019	32.685274542958496
2020	33.512291940967245
2021	32.17461249560705
2022	32.59310860375423