Utah's murder rate is one-third the national average. Robberies and aggravated assault are at less than half the nation's rate. But in a state that prides itself for having some of the safest communities, a new study shows the rates of rape and sexual assault are rapidly rising in Utah.

Since 1991, Utah's rape rate has consistently inched higher than the national rate. By 2002, Utah ranked 14th in the nation for rapes.

According to a study released this week by the Utah Commission on Criminal and Juvenile Justice, between 2000 and 2003 Utah's rape rate grew by 93 percent.

The 54-page study represents one of the most comprehensive looks at rape and sexual assaults in Utah, and its findings shatter common concepts about how rape and sexual assault occur, said Mike Haddon, director of research for the commission.

"Our study shows that victims are rarely attacked by a stranger," Haddon said. The "stranger in the bushes" scenario just doesn't happen nearly as much as people think. "Most commonly, victims are attacked by someone they know, sometimes even family members," he said.

The study mentioned the comparatively low rates of other violent crimes to emphasize the growing problem of sexual assault and rape.

According to the study, the prime victims of sexual assault, which includes mainly fondling, are females around the age of 16. As her age nears 20, the chances of a woman being raped increases.

One surprise in the data, Haddon said, is the lack of age difference between the victim and perpetrator. "The younger the victim, the younger the perpetrator; the older the victim, the older the perpetrator," Haddon said.

The study shows cases of sodomy being nearly evenly split between male and female victims. Same-sex victims made up 18 percent of all cases, with the same narrow age difference seen in opposite-sex cases. "The male-on-male cases were actually younger in age than opposite-sex counterparts," Haddon said.

As for those who offend, the study shows the attacker is often acquainted with the victim and the incidents more often take place at a residence. However, while most cases involve a male with whom the woman is familiar but not in a romantic way, the majority of statutory rapes take place within a "boyfriend/girlfriend" relationship, the study states.

Sex offenders were most commonly males in their mid-20s, and the use of drugs and alcohol was rarely a factor.