The cost of occupying office space in San Francisco soared the most of any market in the world as technology companies such as Salesforce.com and Mozilla Corp. fueled leasing in the city, according to broker CBRE Group Inc.

Occupancy costs — rents plus local taxes and service charges — surged 36.4 percent in downtown San Francisco to $90 a square foot in the year to Sept. 30, Los Angeles-based CBRE said in its semiannual survey of world office markets. That was the biggest jump among 133 areas globally.

Demand from technology-industry tenants is combining with low vacancies and limited new supply to increase rents in areas such as San Francisco and suburban Seattle, which had the fourth-largest rise in occupancy costs, at almost 22 percent. That ran counter to much of the global office market, where a recovery cooled as Europe's debt crisis deepened, banks made cutbacks and emerging-market growth slowed, according to CBRE.