A new report from Minnesota's legislative auditor says the overall economic impact of immigrants in Minnesota is positive, but the study also says the cost of illegal immigrants to state taxpayers is largely unknown. That finding runs counter to a report issued last year by Governor Pawlenty that pegged the annual cost to the state at $188 million. The Office of the Legislative Auditor examined several existing studies on the economic impact of immigrants, and released its analysis today at the state Capitol. Minnesota Public Radio's Tim Pugmire reports.