The sex researchersWilliam Howell Masters (1915-2001) and Virginia Eshelman Johnson (1925- ) conducted laboratory observations of and experiments into human sexual behavior during the 1950s and 1960s.
Their most famous publications were Human Sexual Response and Human Sexual Inadequacy.
... the population is spread out with 22.3% under the age of 18, 8.0% from 18 to 24, 31.0% from 25 to 44, 21.9% from 45 to 64, and 16.9% who are 65 years of age or older. ...