Emperor Keikō (景行天皇) was the twelfth imperial ruler of Japan to appear on the traditional list of emperors. No firm date can be assigned to this emperor and he is regarded by historians as a "legendary emperor". This does not necessarily imply that no such person ever existed, just that there is insufficient material to assign him to a historical period.
... 28.2% under the age of 18, 7.5% from 18 to 24, 33.5% from 25 to 44, 23.9% from 45 to 64, and 6.9% who are 65 years of age or older. The median age is 34 years. For every ...