I like this list (survey of approx. 5000 sufferers, 1% are 50 respondents):
28.70% - Don't know the cause
13.73% - Noise-induced hearing loss (continued noise exposure, occupational noise)
9.59% - Acoustic trauma (explosion, exposure to gunfire or extremely loud, sudden noise)
8.33% - Other (please specify)
7.65% - Virus (ear infection, flu, cold)
6.42% - Spontaneous onset (no apparent cause)
4.84% - Psychological (stress, anxiety, depression)
4.56% - Ototoxic (from drugs or medication)
2.87% - Age-related hearing loss
2.79% - Head or neck injury
2.39% - Sudden hearing loss
2.31% - Meniere's
1.47% - TMJ (issues with the jaw)
1.00% - Ear wax procedure (syringing, candling or other related procedure)
0.68% - Dental treatment
0.66% - Barotrauma (due to change in barometric or water pressure)
0.62% - Ear wax build up
0.60% - Otosclerosis
0.40% - Allergy
0.38% - Metabolic (diabetes, thyroid, B12, hyperlipidaemia etc.)
28.70% - Don't know the cause
13.73% - Noise-induced hearing loss (continued noise exposure, occupational noise)
9.59% - Acoustic trauma (explosion, exposure to gunfire or extremely loud, sudden noise)
8.33% - Other (please specify)
7.65% - Virus (ear infection, flu, cold)
6.42% - Spontaneous onset (no apparent cause)
4.84% - Psychological (stress, anxiety, depression)
4.56% - Ototoxic (from drugs or medication)
2.87% - Age-related hearing loss
2.79% - Head or neck injury
2.39% - Sudden hearing loss
2.31% - Meniere's
1.47% - TMJ (issues with the jaw)
1.00% - Ear wax procedure (syringing, candling or other related procedure)
0.68% - Dental treatment
0.66% - Barotrauma (due to change in barometric or water pressure)
0.62% - Ear wax build up
0.60% - Otosclerosis
0.40% - Allergy
0.38% - Metabolic (diabetes, thyroid, B12, hyperlipidaemia etc.)