A comprehensive study showed that Americans on the average engage in sex 5-9 times a month. "No group in society, we find, has anything more than modest amounts of sex with a partner. And the group that has the most sex is not the young and the footloose but the married." (p.112) "We found that Americans fall into three groups. About a third have sex with a partner at least twice a week, a third have sex with a partner a few times a month, and the rest have sex with a partner a few times a year or have no sexual partners at all." (p.114)
(Sex in America: A Definitive Survey, Robert T. Michael, John H. Gognon, Edward O. Laumann, and Gina Kolata, Little, Brown and Company: New York, 1994.)
When avoiding a pregnancy, a couple is advised to abstain from intercourse and genital contact during the wife's menstruation (3-7 days), during the fertile time (6-8 days), and any day after genital contact before the fertile time. The numbers of days of abstinence for individual cycles vary. On the average there are more than the 5-9 days a month available for conjugal love without achieving a pregnancy.