A report out today shows that eight out of every ten perpetrators of sexual violence are known to those they abuse.
The figures for 2006 were published in the first comprehensive national report by the Rape Crisis Network.
A spokesperson said these findings dispel the myth that most sex abusers are strangers.
The findings in today's report are drawn from 14 Rape Crisis Centres nationwide.
More than 1600 people received counselling in 2006. Some 87% of those who received counselling were women.
While 97% of the abusers were men.
The report showed that nearly half of those who sexually abused children were family members.
One in ten of these children went on to experience sexual violence in adulthood.
The report found that almost 80% of the victims of child sex abuse knew the perpetrator.
Two thirds of the survivors of adult sexual violence knew their attackers.
More than half of those who had confided in someone about their experience went on to contact a Rape Crisis Centre.
Younger people looked for support earlier and the report concludes that the sooner help is sought the less negative the impact on the rest of victim's life.
