Washington’s minimum wage increased 15 cents to $9.19 an hour beginning Tues., Jan. 1.

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 $7.81 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 1.67 percent during the 12 months ending Aug. 31, 2012.

The minimum wage has changed many times over the past decade: an increase of 18 cents to $6.90 an hour in 2002; an increase of 11 cents to $7.01 an hour in 2003; an increase of 15 cents to $7.16 an hour in 2004; an increase of 19 cents to $7.35 an hour in 2005; an increase of 28 cents to $7.63 an hour in 2006; an increase to $8.07 in 2008; an increase of 48 cents to $8.55 an hour in 2009; an increase of 12 cents to $8.67 an hour in 2011; and an increase of 37 cents to $9.04 an hour in 2012.

More information is available online at lni.wa.gov.