Full context:   In Norway, a 20-year longitudinal study of 400 people found that bodily failure and greater dependence became prevalent in the 80+ years. The study calls these years the "fourth age" or "old age in the real meaning of the term". Similarly, the "Berlin Aging Study" rated overall functionality on four levels: good, medium, poor, and very poor. People in their 70s were mostly rated good. In the 80–90 year range, the four levels of functionality were divided equally. By the 90–100 year range, 60% would be considered frail because of very poor functionality and only 5% still possessed good functionality.