Pandora continues to claim audience growth.

Citing audience estimates for June from Triton Digital, Pandora says among 18–49s, the Internet audio service has a weekly cume rating of 25,333,249, a 6% increase from March. Short for “cumulative audience,” cume is a measure of the total number of unique consumers over a specified period.

The June Triton Webcast Metrics local ratings demonstrated growth across all demos in each of the top 10 local markets, according to the company. For each market, Pandora saw Average Quarter-Hour and cume rating increases in the 18–34, 18–49 and 25–54 adult demos, with the strongest gains coming from the 25–54 demo.

Pandora Chief Revenue Officer John Trimble says Pandora’s continued growth in every demographic is “helping the radio advertising industry make informed buying decisions between terrestrial and Internet radio.”

The June 2012 Triton Webcast Metrics ratings are based on listener data from May 24 through June 20 for key radio-buying demos, including adults 18–34, 18–49 and 25–54, Monday–Sunday 6 a.m. – midnight.