Many global estimates put the proportion of Tunisian Berber speakers at less than 1%, perhaps more, taking into account cryptic assumptions and concealment. On the island of Djerba (163,000 inhabitants, 2014), Berber speakers would be 10 to 20,000 in the best estimates, half of them around Guellala. Anyway, that is to say less than 5% of the island population. See for example https://joshuaproject.net/people_groups/12344/TS.
