Growth of high-tech employment helped drive double-digit office rent increases in Boston over the last two years, according to a study released this week by CBRE Group Inc.

Boston ranked seventh out of 20 tech-oriented office markets in rent growth in the 24 months ending in June 2014, with office rents up 11.2 percent. The inventory of high-tech jobs grew 15.7 percent in Greater Boston during the study period, driven by expansion of co-working space in the Seaport District, Financial District and Cambridge.

Top tech leases this year include online furniture retailer Wafair’s 170,000 square feet at Copley Place, VMware’s 70,000 square feet at 5 Cambridge Center and Carbonite’s 53,000 square feet at 500 Washington St. in Boston.

Northern California had the top three markets in rent growth, followed by Manhattan, Denver and Austin, Texas. San Francisco and Austin had the strongest high-tech job growth at 51 and 34 percent, respectively.

The tech sector has accounted for one of every four new office jobs nationally since 2009, and accounted for 20 percent of major leasing activity nationwide in 2014, the report said.

High-tech is the top industry driving demand for office space nationwide, accounting for 20 percent of major leasing activity year-to-date.