People should listen to music for no more than one hour a day to protect their hearing, the World Health Organization (WHO) suggests. It says 1.1 billion teenagers and young adults are at risk of permanently damaging their hearing by listening to "too much, too loudly". It said audio devices , concerts and bars were causing a "serious threat". WHO figures show 43 million people aged 12-35 have hearing loss and the number is increasing. In that age group, the WHO said, half of the people in rich and middle-income countries were exposed to unsafe sound levels from personal audio devices. Meanwhile 40% were exposed to damaging levels of sound from clubs and bars. The proportion of US teenagers with hearing loss went from 3.5% in 1994 to 5.3% in 2006. "What we're trying to do is raise awareness of the problem that is not talked about enough, but has the potential to do a lot of damage that can be easily prevented," said Dr Etienne Krug, the WHO's director for injury prevention. The full report argued: "While it is important to keep the volume down, limiting the use of personal audio devices to less than one hour a day would do much to reduce noise exposure." Dr Krug said: "That's a rough recommendation, it is not by the minute, to give an idea to those spending 10 hours a day listening to an mp3-player. But even an hour can be too much if the volume is too loud." How many people aged 12-35 were most likely to suffer from hearing loss according to WHO?
3.5%. 5.3%. 40%. 50 %.