Year % of revenue 2014 10.762204081407452 2015 6.9514570912155325 2016 9.598250124588962 2017 10.190659730739549 2018 10.84540562301303 2019 12.049746473557994 2020 10.218341623325479 2021 10.944923260740827 2022 4.901851438768682