Kathleen Kennedy (1920 - 1948), Marchioness of Hartington, was the daughter of the former bootlegger and ambassadorJoseph P. Kennedy, Sr.[?] and, thus, the sister of the U.S. president John F. Kennedy. She married William Cavendish (1917-1944), Marquess of Hartington and son of the 10th Duke of Devonshire, who was killed in action in World War II. She died in an airplane crash four years later.
... the age of 18, 5.0% from 18 to 24, 29.0% from 25 to 44, 24.2% from 45 to 64, and 12.7% who are 65 years of age or older. The median age is 39 years. For every 100 females ...