The overweight or obese population is defined as the inhabitants with excessive weight presenting health risks because of the high proportion of body fat. The most frequently used measure is based on the body mass index (BMI), which is a single number that evaluates an individual's weight in relation to height (weight/height², with weight in kilograms and height in metres). Based on the WHO classification, adults with a BMI from 25 to 30 are defined as overweight, and those with a BMI of 30 or over as obese. This indicator is presented both for "self-reported" data (estimates of height and weight from population-based health interview surveys) and "measured" data (precise estimates of height and weight from health examinations) and is measured as a percentage of the population aged 15 years and older.