Figures have been released as part of an annual report by the HSE.
24 per cent of the people treated in sexual assault treatment units last year were under 18.
According to a new annual report, 20 victims were over the age of 55.
734 patients were treated in the HSE's six sexual assault treatment units last year.
277 were seen in the Rotunda Hospital in Dublin, with the next highest being the 111 in the South Infirmary Victoria University Hospital in Cork.
The units in Mullingar, Galway, Letterkenny and Waterford all saw at least 78 patients each.
In total, 92 per cent of the victims were female, and 8 per cent were male.
12 victims were less than 14 years old, 77 were aged between 14 and 16, and 87 were between 16 and 18.
Six were over the age of 70.
9 per cent of the assaults were committed by multiple attackers.
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