According to a WHO report from 2000, the estimated prevalence of ‘adult onset hearing loss for adults aged 15 years and’ older was 7.1 for adults aged 41 and older, 1.4 for people aged 61 and older and 0.1 for people aged 81 and older (Mathers et al., 2000, p.8).

References:

Mathers, C., Smith, A. & Concha, M. (2000). Global burden of hearing loss in the year 2000, Geneva: World Health Organization. https://www.who.int/healthinfo/statistics/bod_hearingloss.pdf