The number of housing permits issued by the city of Boston last year spiked to levels not seen since the 1990s, largely a result of a push from Mayor Martin J. Walsh to increase building in the city to ease its surging cost of housing.

Walsh’s office announced on Dec. 30 that 5,349 permits for new houses, apartments and condominiums were issued last year, which is 17 percent more than the previous 2000s high experienced in 2015 when the housing market was gaining steam post-Great Recession, The Boston Globe reported.

Despite the increase in permits issued, Walsh remains focused on affordable housing in the city, which has one of the highest costs of living in the United States.

Since the 2000s’ previous permit high in 2015, the city has bolstered its focus on such housing, including through its stronger inclusionary development policy, which requires market-rate developers to include affordable units in projects, according to the Globe. Since then, the city has collected $56.6 million from developers and created 2,124 affordable homes.

“While our population is growing faster than ever, we have been working to meet the housing demands of our growing city,” Walsh said in a statement. “I believe that Boston’s growth must benefit everyone who lives here, and I’m proud that we are building housing for a range of incomes.”