I'm not sure about that but at some point the woman has to make a choice. Either file a report or forfeit your right to prosecute later. The world is not gonna stand still for 20 years while she makes up her mind.Filing a police report places the details of the traumatizing incident in the public domain. There are a lot of reasons why a crime victim would elect to not create a record that anyone can access if doing so doesn't improve their situation.A woman can report it to law enforcement without pursuing prosecution. This is often the case when an assault is difficult to prove, then if the attacker is later prosecuted for another assault, the woman can then press charges and a conviction is more likely. If she does not report it, she can't come back 20 years later and expect to be taken seriously.I've always presumed that unreported means not reported to law enforcement. Victims however can relay their experiences to their physicians, to a therapist if they require counseling to deal with the trauma of a sexual assault, a psychologist, members of a support group, counselor, etc.How do you know they're unreported if no one reports them?Most rapes are unreported even today. Most sexual assaults are unreported even today, most sexual harassment at work is unreported even today.
It's only because of the way our society is structured that so many people believe unless there is a police report then nothing "serious" happened.