Not percentages, but different degrees are used to describe hearing loss. Alterations in hearing loss across pitches can range from mild to moderate to severe to profound. It is determined by a quick hearing test by comparing the volume loss you have to the average of many adult listeners with healthy auditory systems. Cortexi
https://www.mid-day.com/brand-media/article/cortexi-reviews-fake-or-legit-users-shocked-23278387