National radio ad buys placed by agencies were up 15% year-over-year in February, totaling $128.7 million. What drove the gain? Three key ad categories doubled their spend on radio last month, compared to the same period one year earlier, according to Standard Media Index.

Casual dining restaurants, consumer electronics and entertainment each doubled their year-over-year national radio allocation in February 2018, according to new data provided to Inside Radio by SMI. But they weren’t alone in allocating more dollars to the medium last month. Telecom upped its radio outlay by 27%, making it radio’s biggest spending category in February. That’s more than five times the growth rate for telecom across all media platforms – the category grew 5% in February, making it the month’s top overall advertiser.

Specialty retail was radio’s second largest national advertiser in February, despite a 27% decrease. Quick serve restaurants were third, up 43%; followed by insurance, which spent 35% more on national radio buys. Auto, a key category for radio and all media, was fifth with a 33% decline.

While telecom and auto were top categories for both radio and the entire media sector, there were some key differences when comparing radio to the larger media universe. Across all media platforms, telecom was February’s biggest spending category, increasing its ad outlay 5% year-over-year. No. 2 automotive was also up 5% during the month. Ad spending by prescription pharmaceuticals rose sharply, up 19% across all media platforms, followed by food, produce & dairy (+8%). Consumer electronics delivered the largest year-over-year increase, doubling its allocation in February year over year.

SMI’s figures don’t include direct sales—and thus represent an incomplete picture of radio ad spend. But the firm’s monthly reports are a good barometer of national ad buys and how individual ad categories are trending.

Driven by gains in national television, digital and radio, the national ad market grew 8% year-over-year in February, excluding Olympics-related advertising.