Original: Ibid, Table 142, p. 499, and p. 474 Marital coitus The average frequency of marital sex reported by women was 2.8 times a week, in late teens; 2.2 times a week, by age 30; and 1.0 times a week, by age 50.
Simplified: How often they have sex: Women reported to have had sex 2.8 times a week (in the late teens), 2.2 times a week by age 30, and once a week by age 50.