LOS ANGLES, CA - Los Angeles’ city council has voted to increase its minimum wage from $9 to $15 an hour by 2020. Cities like San Francisco and Seattle have made similar changes to their minimum wages, but LA’s population of almost 4 million makes this by far the most significant development in the movement for an increasing minimum wages.

The increase passed in a 14-to-1 vote, and comes during a time where America’s workers are rallying for higher wages in several high-profile companies. Dozens more cities are considering wage hikes, and in 2014, even states like Alaska and South Dakota raised their state-level minimum wages by ballot initiative.

“The effects here will be the biggest by far,” said Michael Reich, the University of California Economist commissioned by city leaders to research potential effects of the wage increase. “The proposal will bring wages up in a way we haven’t seen since the 1960s. There’s a sense spreading that this is the new norm, especially in areas that have high costs of housing.”

But according to The New York Times, opponents of higher minimum wages, including the Los Angeles Chamber of Commerce, are concerned that the increase may turn Los Angeles into a “wage island,” pushing businesses to nearby places where they can pay employees less.

“They are asking businesses to foot the bill on a social experiment that they would never do on their own employees,” said Stuart Waldman, the President of the Valley Industry and Commerce Association.

This 67 percent increase from California’s minimum will be phased in over five years, first to $10.50 in July 2016, then to $12 in 2017, $13.25 in 2018, and $14.25 in 2019. Businesses with fewer than 25 employees will have an extra year to carry out the plan. The New York Times reports that starting in 2022, LA’s annual increases will be based on the Consumer Price Index average of the last 20 years.