The economic downturn that has put an unprecedented number of Idaho workers in line for unemployment benefits will drive the tax rates that employers pay to support the benefit program up 70 percent, said Roger Madsen, director of Idaho Department of Labor.

Madsen announced the rate increase Wednesday to the Governor's Workforce Development Council in Boise.

The across-the-board increase in the more than a dozen rate classes is mandated by legislation developed by business and labor and approved unanimously by the Legislature in 2005. In conjunction with the increase in employer tax rates, the maximum weekly benefit for workers will decline about 3 percent.