Year	% of revenue
1997	84.33880817014108
1998	83.80179054757443
1999	82.32675471138151
2011	85.72653262747761
2012	84.56576804641772
2013	83.40961303630539
2014	82.94201042723941
2015	92.16427108928315
2016	92.2118691126935
2017	91.80272044333458
2018	91.88685751733509
2019	77.10667416496204
2020	76.66433658657454
2021	72.05764590135041
2022	78.6026369044077