This report extends the development of normative standards for estimating occupational hearing loss using data from the United States National Health and Nutrition Examination Survey (NHANES) conducted by the National Center for Health Statistics. A proposed revision of the International Organization for Standardization (ISO) 1999:2013 standard ("Acoustics-Estimation on noise-induced hearing loss") uses a linear interpolation of hearing threshold data to estimate the 25th and 75th percentiles for men and women at 500, 1000, 2000, 3000, 4000, 6000, and 8000 Hz. This paper revisits the NHANES data to provide these estimates, avoiding other types of interpolations that could misrepresent the population data.