TUMWATER — Washington’s minimum wage will increase 15 cents to $9.47 an hour beginning Jan. 1, 2015, the Department of Labor & Industries (L&I) announced Sept. 30.

L&I calculates the state’s minimum wage each year at this time as required under Initiative 688, which Washington voters approved in 1998. The change reflects a 1.59 percent increase in the federal Consumer Price Index for Urban Wage Earners and Clerical Workers (CPI-W) over the last 12 months ending Aug. 31.

The federal Bureau of Labor Statistics announced the change in the CPI earlier this month.

The change will affect more than 67,000 workers, based on full-time equivalent positions according to the Washington State Employment Security Department. The per hour increase will total $312 per year.

The minimum wage applies to workers in all industries, including agriculture, although 14- and 15-year-olds can be paid 85 percent of the adult minimum wage, or $8.05 an hour.

Washington has the highest state minimum wage in the nation, followed by Oregon, where the minimum wage will increase to $9.25 — an increase of 15 cents in 2015.

Washington is one of at least 10 states that adjust the minimum wage based on inflation and the CPI. Others include Arizona, Colorado, Florida, Missouri, Montana, Nevada, Ohio, Oregon and Vermont.

L&I enforces the state’s wage-and-hour laws. The agency investigates all the wage-payment complaints it receives, as required by state law. Workers can file a wage complaint online at www.lni.wa.gov/workplacerights/, or by calling 1-866-219-7321.

More information on minimum wage is available at Wages.lni.wa.gov.

Employers and workers also may call 360-902-5316 or 1-866-219-7321.