Digital revenue still doesn't yet account for 5% of U.S. radio broadcasters' revenue. But it was up 16% in the second quarter of 2013, and up 13% in the first half of the year. It was radio's only revenue sector that gained in Q2.
The RAB says spot and "off-air" (events, etc.) radio revenue were flat for the quarter, with network revenue off 4%.
You can see the RAB's report here.