As of Jan. 1, Washington’s minimum wage increased 37 cents to $9.04 an hour.

Washington’s minimum wage applies to workers in all industries, including agriculture, although 14- and 15-year-olds may be paid 85 percent of the adult minimum wage, or $7.68 an hour.

The Department of Labor & Industries adjusts the state’s minimum wage each year in September as required by Initiative 688, which Washington state voters approved in 1998. The initiative requires the state to adjust the minimum wage according to the change in the federal “CPI-W,” which is a national index covering the cost of goods and services needed for day-to-day living. That index rose 4.258 percent during the 12 months ending Aug. 31, 2011.