A proposal to raise San Francisco’s minimum wage to $15 an hour would cost about 15,270 jobs concentrated in the low-wage restaurant and food-service industries by 2019, according to the city’s controller. While the plan to raise the wage in California’s fourth-largest city from $10.74 to $15 by 2018 would boost employee earnings and consumer spending, the additional expenses would discourage job creation, according to a report today by the Controller’s Office of Economic Analysis. “To the extent that higher minimum wage raises labor costs, it will create a disincentive to hire employees and would lead to reduced employment,” the report said. The proposal, offered last month by Mayor Ed Lee for the November ballot and pending before the Board of Supervisors, would bolster pay in a city where the cost of living has soared in recent years from an influx of highly paid technology workers. The push is part of a nationwide effort in cities including Seattle and Chicago to help low-wage workers that is backed by President Barack Obama. “San Francisco is the most progressive city in America when it comes to addressing income inequality,” Lee, 62, said in a statement. “We are going to help our lowest-paid workers.” As many as 11 percent of San Francisco workers, or about 60,000 people, earned the minimum wage last year, according to the report. They were employed in industries including restaurants and bars, manufacturing and repair services.