The Population Reference Bureau's 2010 World Population Data Sheet focuses on a rapidly aging world, highlighting many countries' pressures to care for their elderly citizens. According to the data sheet, the elderly support ratio—the number of working-age people ages 15 to 64 divided by the number of people 65 or older—is declining in many countries, most notably in developed countries. According to PRB estimates, by 2050 Japan will have the lowest ratio of one working-age adult per elderly person, while Niger, a developing country, will still have a ratio of only 19. No country will have an elderly support ratio above 20 by 2050.
While the elderly support ratio is significant in indicating levels of potential support from society available for the elderly, and has implications for public programs, it does not incorporate informal care. The elderly support ratio does not capture the number of people ages 85 and older who may require the most resources of care, for longer periods of time. Researcher Jean-Marie Robine and his colleagues have refined the elderly support ratio, and have introduced the "oldest-old support ratio," the number of people ages 50 to 74 to the number of people ages 85 and older. This measurement is more specific and provides information on the number of middle-aged people available to care for one person in the oldest age group.1