MILWAUKEE (AP) -

Nearly 80 children in Milwaukee were sexually exploited in the two-year period ending Aug. 1, 2012, according to a new report that examined for the first time the extent of sex trafficking in Wisconsin's largest city.

The report found that 77 children were sexually exploited between Aug. 1, 2010, and Aug. 1, 2012, according to a story by the Milwaukee Journal Sentinel on Tuesday.

"That 77 over a two-year period is just a fraction of the number of minors who have been sex-trafficked," said Claudine O'Leary of Rethink Resources, an organization that offers training to assist youths and adults who have been sexually exploited.

The study was admittedly limited, taking information only from Milwaukee police reports. It did not include any ongoing cases or any of the federally investigated or federally prosecuted sex trafficking cases.

The report found that children who were involved in sex trafficking were primarily black girls 12-17 years-old who lived on Milwaukee's north side.

The numbers are hard to track. Sex trafficking is often misreported to law enforcement or social service providers as a battery or domestic violence incident, said Milwaukee police Det. Lynda Stott.

The study was paid for by the Bob and Linda Davis Family Fund and the Bureau of Milwaukee Child Welfare. The Milwaukee Homicide Review Commission examined Milwaukee police incident reports from the two-year period that related to youths who as defined by state law were recruited or encouraged to take part in a commercial sex act or sexually explicit performance.

Child sex trafficking continues to be a big business in the state. Just over a week ago, 10 children in Wisconsin were recovered from child trafficking and 100 suspects were arrested as part of a nationwide FBI investigation.