A note of correction with reference to parameters of the menstrual cycle and the efficiency of rhythm methods of contraception

It is known that further mortality reductions in industrialized countries depend heavily on trends in mortality rates at the oldest ages. In this article, a model proposed by Coale and Kisker is used to investigate mortality trends at the extreme old age of 110 years. The most important conclusions are that (1) the form of the model proposed by Coale and Kisker fits observed mortality schedules very well indeed, and (2) the trend in mortality rates at extremely high ages has apparently been flat for men, but may have declined slightly for women during this century.