Nine out of 10 victims of recent sexual violence reported last year were women, according to the Central Statistics Office.
New CSO figures show a quarter of sexual violence crimes reported in 2018 took place 10 or more years before they were reported to gardaí.
A third of women who reported the crime within a year of it happening were aged between 18 and 29.
Up to 32% were under 18 while just under a quarter were 30 years old or more.
Sam Scriven, a statistician at the CSO, said: “In 2018, 77% of homicide victims and 59% of victims of reported physical assault and related offences were males. However, more than 4 in 5 victims (82%) of reported sexual violence incidents were females.
“The reporting of sexual violence encompasses the reporting of incidents which occurred recently as well as the reporting of historic cases of sexual violence.
“A quarter of sexual violence reported in 2018 referred to incidents which took place 10 or more years prior to being reported to An Garda Síochána, and the vast majority of these cases took place when the victim was aged under 18 years.”