AGAINST THE backdrop of a steady increase in rapes reported to police, authorities believe that the number of reported rapes by acquaintances is growing even faster. But they're undecided on whether it's a higher incidence in assaults or a heightened willingness to report them that's most responsible for the increase in the rape statistics.
Incidents of forcible rape as tabulated by the FBI's uniform crime reports increased in all but five years of the last three decades. In 1989, the last full year for which data is available, the FBI recorded 94,500 forcible rapes -- the highest ever.
Neither the FBI nor the Bureau of Justice Statistics categorizes rapes according to whether the victim knew her attacker.
Building on figures from studies conducted by Dr. Mary Koss, a professor of psychiatry at the University of Arizona, Robin Warshaw, author of "I Never Called It Rape," estimates that women "are actually four times more likely to be raped by a man they know than by a stranger."