Raw steel production in the Great Lakes region shot up to 628,000 tons last week.

Local steel output remains much lower than normal amid a deluge of imports that now account for a record one-third of the total market share. Overall U.S. production trails 2014 by 7.2 percent.

Great Lakes steel production rose by 15,000 tons, or 2.4 percent, in the week that ended Saturday, according to an American Iron and Steel Institute estimate. Overall U.S. steel output rose by 1.5 percent over the same period.

Most of the raw steel production in the Great Lakes region takes place in the Chicago area, mainly Lake and Porter counties in Northwest Indiana. Indiana has led the nation in steel production for more than 30 years.

Production in the Southern District, which encompasses mini-mills across the American South, dipped to 573,000 tons last week, down from 575,000 tons the week before.

Total domestic raw steel production last week was about 1.732 million tons, up from 1.705 million tons a week earlier.

Nationally, domestic steel mills had a capacity utilization rate of 73.3 percent last week, up from 72.1 percent a week earlier. The capacity utilization rate had been 77.3 percent at the same time a year earlier.

Year-to-date output was 34.9 million net tons, at a capacity utilization rate of 72.3 percent, according to the American Iron and Steel Institute.