The link does clarify a bit about what they mean. “the scatter of prevalence estimates is wide, although most study results have shown rates of between 10% and

The link does clarify a bit about what they mean. “the scatter of prevalence estimates is wide, although most study results have shown rates of between 10% and 15% of the adult population. The largest and most scientifically reliable study was undertaken as part of the National Study of Hearing in England (n=48 313).3 The results of the study showed a prevalence of 10·1% among adults, with the tinnitus described as moderately annoying by 2·8% of respondents, severely annoying by 1·6%, and at a level that severely affected ability to lead a normal life by 0·5%. Results from studies in Egypt,4 Japan,5 and Nigeria,6 indicate tinnitus prevalence is broadly similar in these countries to in Europe and the USA.”