Advertising-supported tiers made up 46% of streaming subscriptions at SVOD platforms that offer both options — with and without ads — at the end of March, up by 33%, or 7 percentage points, year-on-year. Over the past nine quarters, ad plans drove 71% of net subscriber additions for premium SVOD (streaming video-on-demand), according to the latest State Of Subscriptions report from leading market research firm Antenna.