On January 1, minimum wage salaries go up in 13 states, 4 cities

SEATTLE -- While most of the increases amount to less than 15 cents per hour, workers in places like New Jersey, Connecticut, New York and Rhode Island will see a bigger bump.

Earlier this year, New Jersey residents voted to raise the state's minimum wage by $1 to $8.25 per hour. And lawmakers voted to hike the wage by between 25 cents and 75 cents per hour, to $8.70 in Connecticut and $8 in Rhode Island and New York.

Residents in Arizona, Colorado, Florida, Missouri, Montana, Ohio, Oregon, Vermont and Washington will see a higher wage floor due to annual cost of living adjustments.

The Economic Policy Institute, a left-leaning think tank, used Census data to estimate that the increases will boost the incomes of 2.5 million low-wage American workers next year.

Currently, 19 states have minimum wages set higher than the federal level of $7.25 per hour. Once the changes take effect on Jan. 1, the number rises to 21.

Wage increases are also set to take place at the local level. Voters recently approved a raise to $15 per hour for many workers in SeaTac, a tiny town centered around the Seattle-Tacoma airport in Washington. A judge ruled this past week that parts of the measure were not valid: The city could impose the minimum wage for some of the affected workers, the judge said, though not all. Supporters of the increase plan to appeal.

The push for $15 an hour could soon move beyond the one small town. Seattle's mayor-elect has said he plans to also raise the city's minimum wage to $15. Washington currently has the highest state minimum wage at $9.19 per hour.

Workers in San Francisco, San Jose and Albuquerque will also see wages go up.

Later in 2014, several other locales, including two counties in Maryland and Washington D.C., will raise their minimum wages. California is set to raise its minimum wage to $9 in July.

The piecemeal increases at the local level are occurring amidst a national debate over low wages and income inequality. Fast food and retail workers have been staging protests and walking off work for more than a year, calling for better pay and more hours.

Currently,fast food workers nationally earn an average of about $9 per hour. In September, Bill Simon, president and chief executive officer of Wal-Mart U.S., said that less than half of the company's U.S. employees make more than $25,000 per year.