ANCHORAGE  The state has long suffered the highest sexual assault rate in the nation, and the problem is worst in rural areas, according to a report released Tuesday. The numbers are unacceptable, troopers said at a news conference Tuesday detailing the study. "Each of us has a role in ending sexual violence in Alaska," said trooper Col. Audie Holloway. "We need to think into the future." In nearly 1,000 cases studied over two years, the average age of victims was 16, while the average age of those accused was 29. In four out of five cases, the suspects were relatives, friends or acquaintances. Overall, 89% of the victims were female. One out of three cases were reported more than a month after the abuse occurred, leaving evidence hard to collect. The study, conducted by the University of Alaska Anchorage's Justice Center, looked at 989 sexual assault cases reported to state troopers in 2003 and 2004. Researchers did not look at cases reported in the same period to municipal police departments, including those in Anchorage or other urban centers that account for 80% of Alaska's 670,000 residents. Overall, 46% of the cases were referred for prosecution. Of those 452 cases, about half resulted in convictions. The study is believed to represent only a fraction of abuse actually committed in trooper jurisdiction. Still, Alaska has had the nation's highest per capita occurrence since 1995. According to statewide figures for 2003 and 2004 alone, there were 89 rapes per 100,000 people, almost three times the national average of 32 per 100,000, said Andre Rosay, the Justice Center's interim director. "There are a lot of excellent programs here, so it could be reporting rates are higher here. We don't know, though," he said. "But even if there are higher reporting rates, our rates far surpass those in the lower 48." Just less than half the cases studied occurred in the troopers' immense, sparsely populated western area known as the C Detachment. The largely native region contains a third of the state's land mass, stretching from Kotzebue in the north to the Aleutian Islands chain. With few communities connected by roads, about 50 troopers working in the region must fly to villages to respond to crimes beyond the scope of village safety officers. Capt. Steve Arlow, commander of the detachment, said the numbers were not surprising. Sexual assaults account for the bulk of work done by troopers, he said. "Our troopers are out there dealing with it every day," he said. Michelle DeWitt, director of the Tundra Women's Coalition, said that sexual crimes are about power and that many in the region feel increasingly powerless as native cultures are undermined. The coalition runs a regional emergency shelter in Bethel, a commercial hub for the western region. Another huge problem, she said, arises when the accused is known to the victim. That dilemma is intensified for those living in tiny villages. "When a victim knows who harmed them and they live in a small community where everyone is related, they know that if they report that they were harmed, then other community members will be impacted," DeWitt said. "Knowing that someone may be removed from the community makes it very difficult to talk about it." Copyright 2008 The Associated Press. All rights reserved. This material may not be published, broadcast, rewritten or redistributed. Conversation guidelines: USA TODAY welcomes your thoughts, stories and information related to this article. Please stay on topic and be respectful of others. Keep the conversation appropriate for interested readers across the map.