ST. PAUL, Minn. — More than 15,000 nurses at 15 Twin Cities. Duluth and Superior hospitals began athree-day strike. The strike is thelargest by private-sector U.S. nurses in history. The Minnesota Nurses Association targeted large hospitals whose union contracts had expired. A settlement would set a model for MNA contracts at smaller hospitals elsewhere. The strike is set to last three days, until Thursday at 7 a.m., the union said.

Earlier: Nurses target big hospitals for strike

Strike issues

Nurses originally sought as much as 37% more in salaries over three years but came down to 30% in negotiations. Hospitals countered with 10% over three years. Contracts vary by hospital. Other issues include benefits and staffing levels.

Current salaries

Registered nurse in Minnesota average $39.40 an hour, which works out to $82,000 a year, according to the state jobs department.

Negotiations. Hospitals and union remain far apart.