In a certain noisy factory, workers are provided with earplugs and are expected to wear them. An industrial hygienist inspecting the plant found that 100 of the 500 workers in the factory wee not wearing their earplugs because they regarded them as uncomfortable and a nuisance. When all the workers were given a hearing test, it was found that 16 of the earplug wearers and 40 of the nonwearers had developed significant hearing loss. All had normal hearing at their preemployment examinations 4 years earlier, when the plant opened. What proportion of the hearing loss in all the workers was attributable to not wearing earplugs?